Archive "Weather" (Page 2)

Weather: Austria, Liechtenstein

The broad-brush picture of weather in Austria is fairly straightforward; it's the delicate strokes that can throw a visitor. On the large scale, Austria features a Swiss-style mountainous regime to the west and a central European lowland climate to the east. The Tyrol region of western Austria – and Liechtenstein just beyond – is crisscrossed […]

Weather: Europe

By and large, European weather obeys the dictum “moderation in all things”. When compared to other mid-latitude continents, Europe is indeed a favoured child. Tornadoes, hurricanes and blizzards may fling themselves at the United States; China may endure intense heat and brutal cold; but most of Europe trundles along with relatively few weather worries. In […]

Weather: Caribbean/Atlantic Islands

Aruba | Bahamas | Bermuda | Cuba | Dominican Republic | Haiti | Jamaica | Netherlands Antilles The homogeneous cultures that extend across much of the Caribbean have been shaped in part by a beneficent climate. Across this great arc of islands, temperatures gradually rise and fall from pleasantly warm levels in January to readings […]

Spinning fiction out of Colombian climate

The fractured mix of coastline and mountain across northernmost Colombia and Venezuela is laced with small-scale weather regimes that violate the normal rules of climate. As the childhood home of novelist Gabriel Garcia Marquez, this land was fertile ground for the blend of magic and realism that permeates his writing. Garcia Marquez grew up in […]

Weather: Venezuela, Colombia, French Guiana, Guyana, Suriname

The usual ingredients of tropical climate – sharp moisture contrasts, temperatures that hang steady – come together in intriguing ways through the belt of countries across the north end of South America. The Caribbean coast of Venezuela and Colombia is famous for its oddly dry climate, with striking differences in rainfall across short distances. Although […]

Weather: Peru

For a country fronting a tropical ocean, it's amazing that coastal Peru is as dry as it is. Some towns along the Pacific go years without measurable rain. The desert air, shaped by cold waters moving north along the coast and welling up from below, tends to be humid, yet mild, for its tropical latitude. […]

Weather: Ecuador/Galapagos

South America's climatological contrasts seem to converge on this small Pacific nation. The northernmost tip of coastline gets well over 1000mm/39in of rain a year. Further south along the coast, the amounts drop off drastically. Manta averages less than 300mm/12in, although the rains are much heavier just inland. The coast is more moist and more […]

Weather: Chile

This is the world's most linear country: Chile spans 38° of latitude but less than 2° of longitude at its narrowest point. All along that length, the Andes and the Pacific face off. This means the gradual transition from sub-tropic to sub-polar along Chile's length is rivalled by the changes that occur in a short […]

Weather: Brazil

Roughly as large as the United States or China, Brazil is by far the world's largest nation straddling the equator. For all its size, however, Brazil has relatively few weather surprises, thanks to its low latitude and the absence of any huge mountain ranges. Amazonia and Mato Grosso The northwest third of Brazil is dominated […]

Weather: Bolivia

Situated entirely east of the Pacific coastal desert, Bolivia divides neatly into lowland and highland regimes. The lowlands include rainforest across the northeast and the Chaco grasslands across the southeast. Both regions are hot and humid – it often climbs above 40°C/104°F across the Chaco from September to December – and both get plenty of rain […]

Weather: Argentina

If any part of South America approaches the four-season regime familiar to Americans and Europeans, it's the heart of Argentina. Most of the country gets recognizably warm in summer and cool in winter, with clear-cut transitions in between. What's more, the bulk of Argentina manages a great deal of sunshine without becoming a desert. Some […]

Weather: South America

Bone-dry deserts overlooking tropical oceans, perpetual windswept chill, hushed tropical splendour – South America isn't lacking in climatic variety. As opposed to the chameleon-like seasonal shifts found in Asia and North America, South America specializes in more-uniform climates that maintain their bold, distinctive hues throughout the year. Despite the “South” in its name, a good […]

Weather: Panama

Like a microcosm of Central America, Panama's length is far greater than its breadth. The country snakes its way from west to east, putting the Atlantic to its north and the Pacific to its south (if you're sailing from Europe to Asia, you actually end up further east after going through the Panama Canal). The […]

Weather: Guatemala, Honduras, El Salvador

The highlands of the sierra at the heart of Guatemala provide a refreshing change from the muggy air that loiters at sea level. At a typical sierra altitude of 1500m/4900ft – the height of Guatemala City – most nights drop below 15°C/59°F in winter and 18°C/62°F even in summer. Afternoons warm up nicely year-round, but […]

Weather: Costa Rica,Nicaragua

For all the renowned ecological diversity of this small nation, its meteorological diversity is worth noting as well. This is a country where micro-climates reign supreme. The combination of an irregular coastline, the presence of two contrasting bodies of water nearby, and the extremely varied topography leads to a plethora of local wind and rainfall […]

Weather: Belize

Weather: Belize

Cays and coral reefs are one of the main tourist draws here, so the heat and humidity that rule Belize almost year-round aren't necessarily a drawback. The dry season is shorter than usual for Central America. Summer and autumn deliver a downpour about every alternate day, and in winter a few fronts push south from the […]

The wet season’s “little summer”

If you visit Central America or south and east Mexico during the heart of the wet season, you may find the heavens failing to open up as expected. The afternoon rains typically slacken across much of the region for two or three weeks during July or August, producing the canicula or veranillo (literally, the little […]

Weather: Central America

On a global scale, Central America might seem to be little more than a thread of land connecting the much larger fabrics of North and South America. Yet clinging to this thread is a spectacular array of landforms, cultures and micro-climates. As you'd expect for a region lying wholly between the Tropic of Cancer and […]

Weather: The United States

Entire shelves of books have been written about United States weather. In part, that's because the country is both sprawling and populous. The nation's agricultural roots and high mobility also play into its obsession with the atmosphere. But the weather itself deserves some credit. Europeans who settled America from east to west were progressively amazed […]

The great American thermometer race

Roadside kitsch is a US tradition and the country's oversized weather extremes are a natural source of material. At least two tornado “museums” sprang up during the 1990s, for instance. On your way to Death Valley, California – the hottest spot in the Americas – it's difficult to miss the world's largest thermometer display. Erected […]

Weather: Mexico

You'll be hard-pressed to find a blizzard or a tornado in Mexico. Unlike its neighbours to the north, Mexico gets few of the wild temperature swings that play out across the mid-latitudes. Hurricanes are not to be taken lightly in Mexico, however: they can cause major destruction along the east-facing coastlines of the Gulf of […]

Weather: Canada

The worlds second-largest country, Canada has the worlds most extensive coastline, fronting the Atlantic, Pacific and Arctic Oceans. This provides plenty of raw material for a varied climate, much like that of the United States, but colder and drier on average. Storm systems often spin up along the nations southern tier (especially in Alberta) before […]

Weather: North America

North Americas mercurial climate has something for everyone. Severe hurricanes, killer tornadoes, crippling snowstorms, torrential downpours, withering drought and a fair share of nice weather, too – all pay frequent visits to this prosperous, yet vulnerable, land that stretches from the Canadian Arctic to tropical Mexico. Hollywood has bombarded the world with films of extraordinary […]

Computer models

Your weathercaster might have more charisma, but computer models are the building blocks of almost every weather forecast you'll ever get on TV or anywhere else. Modern meteorology would be impossible without them. A computer model that predicts the weather is nothing more or less than a miniature replica of the atmosphere. Models are each […]

Forecasting by the numbers

While employed as an ambulance-driver for the French army during World War I, Lewis Fry Richardson worked on a scheme that's still in use today for predicting weather by computer. Richardson devised seven equations that could be used to extend the current weather into the future. He put his ideas to the test with a […]

Weather chaos

The early 1960s saw a boom in scientific studies, including meteorology, but in the background one particular sceptic was raising eyebrows. Edward Lorenz, a professor of meteorology at the Massachusetts Institute of Technology, discovered what still seems to be an outer limit to useful weather forecasts.The problem Lorenz found later became famous as 'chaos*. When […]

Let’s discuss this storm

For a glimpse into the minds of working meteorologists, the forecast discussions posted by the US National Weather Service each day are unbeatable. NWS forecasters use these to explain the reasoning behind their outlooks, acknowledging what is fairly certain and what might go wrong. Laden with jargon and sometimes sprinkled with weather-nerd humour, these discussions […]

Of hedgehogs and holidays

There's nothing like a gloomy winter to generate the longing for a good weather omen. In certain cultures, February 2 has traditionally filled that role for centuries. It's known in Christendom as Candlemas Day (formerly the Feast of the Purification of the Virgin). Sunshine on Candlemas Day has always signalled an ominous turn of events: […]

The hole in the ozone and what we’re doing about it

The ozone hole is more than a physical concept. It's a powerful symbol of how humans can wreak damage to the planet in ways we never dreamed. Be that as it may, the risks posed by the ozone hole appear to be on the decrease, and in many ways they pale next to the dangers […]

What you can do about climate change

It's the biggest environment challenge our world has ever faced, but that doesn't mean global warming is insoluble. Here are a few ways you can make a difference. Calculate your carbon. Through a variety of online tools, you can determine how much carbon is produced by your daily activities – the perfect starting point for […]

Forecasts for the twenty-first century

The computer models that project global climate don't yet have the skill to issue regional outlooks with much confidence. This means that policy-makers don't work with forecasts per se. Instead, they evaluate 'scenarios”, examples of what could happen if things played out in a certain fashion. Researchers spin whole sets of scenarios under various assumptions: […]

Wild cards

Its human nature to look for an easy solution to global warming. One such idea involves sprinkling tons of iron filings over the ocean to stimulate the growth of plankton that would consume carbon dioxide. Another involves spraying sun-blocking particles from aircraft into the stratosphere, mimicking the temporary cooling effects of strong volcanoes. Yet such […]

The downs and ups of global warming

If scientists knew about the greenhouse effect a hundred years ago, and if it as been obvious for decades that atmospheric C02 is on the increase, why didn't we hear alarm bells ringing sooner? To begin with, the temperature pattern of the twentieth century threw scientists off the trail. The global average rose dramatically from […]

What puts the greenhouse in gas

All molecules of greenhouse gas – ozone, carbon dioxide, water vapour and the rest – have at least three atoms. These molecules capture and absorb radiation more easily than a two-atom molecule like nitrogen or oxygen, making them the prime culprits in global warming. If the/re so effective, why don't these molecules catch energy on […]

Muggy greenhouse

The most prevalent of our greenhouse gases is water vapour. It's responsible for about two-thirds of the natural greenhouse effect. Carbon dioxide is a much more powerful absorber, however, and so a small increase in C02 can have a wider impact.The important thing about water vapour is that it's an agent of positive feedback. As […]

The trace of atmospheric carbon dioxide, measured in parts per million above Hawaii's Mauna Loa since 1957, shows a steady climb, plus yearly rises and falls caused by Northern Hemisphere plant cycles.

The basics

One of the most deceiving aspects of climate change is the aura of controversy surrounding it. In the US, in particular, many journalists have tended to portray global wanning as an either/or proposition: either it's warming or its not, either were to blame or we aren't, either we know what's going to happen or we don't. […]

Will Europe get the big chill?

It's not out of the question that global warming could produce cooling rather than warming across northwest Europe. This strange scenario was first proposed decades ago by geochemist Wallace Broecker, and it was the idea behind the blockbuster 2004 film The Day After Tomorrow, where it played out on a cinema-convenient time scale of a […]

Making your own forecast

More than ever before, it's feasible for a layperson to craft their own weather forecast. The raw material used by the professionals – output from computer models – is available for many parts of the world on the Internet. Anyone can put together a home weather station at reasonable cost and see how their out- […]

The verification game

When a forecaster claims to be '80 percent accurate” what does it actually mean? A whole sub-field of meteorology, forecast verification, is devoted to this question. The guru of verification was the late US researcher Allan Murphy, who claimed a good forecast needs to have consistency, quality and value. Imagine a set of forecasts that […]

Reading between the lines

What kinds of forecasts are available out there? How solid are their claims of accuracy? What do you do when forecasts from different sources disagree? As consumers of weather information, it works to our advantage to ponder the forecasts we get and learn how to use them wisely. To paraphrase the Roman maxim caveat emptor, […]

Only a slight chance of confusion

It is as a direct result of Model Output Statistics (MOS) that the nifty forecast feature known as probabilistic precipitation outlooks exists. Statements like 'a 70 percent chance of rain” now appear in forecasts around the globe. These were launched in the mid-1960s in the United States, where MOS was pioneered. As familiar as they […]

A preview of next year’s climate

If you can't get next week's weather right, how can you claim to predict anything a year in advance? It's the difference between weather and climate that makes long-lead forecasts possible. Actual storms can't be predicted a year out, but the longer-term features that affect climate across a season can sometimes be foretold with surprising […]

The surprise East Coast snow of 2000

The timing was almost perverse. On January 18,2000, the US National Weather Service announced that its latest supercomputer for weather and climate models was officially online. Reaching five times the speed of its predecessor, increases in forecast accuracy were all but assured. Less than a week later, a snowstorm took shape over the eastern US […]

Getting the word out

So you're wondering if it's going to rain tomorrow. You pick up the paper and find a weather report that's a sea of typography. The local forecast must be bobbing around somewhere in there, but you can't find it straight away. You hop onto the Internet and come up against a hundred different Web pages […]

So the sky says

Folklore through the ages has linked the state of the sky to the upcoming weather. The parade of cloud that often precedes a mid-latitude storm – from high, wispy cirrus and patches of cirrocumulus to lower, rain-bearing nimbus – gave birth to the maxim, 'Mackerel scales and mare's tails make lofty ships carry low sails.*The […]

Normally, the boundary between cool, deep Pacific water and warm surface water slopes upward from west to east across the tropics (left). During El Nino, warm water builds in the east, and tropical rainfall shifts east as well.

El Nino and La Nina

Moody, tempestuous, violent: it's so easy to assign human qualities to El Nino and its companion, La Nina. This pair of atmospheric cycles broke into the news in the late 1990s when a remarkably strong El Nina wreaked global havoc. The pithy name fits well with headlines, and the concept – a strange, portentous warming […]

Cycles galore

Europeans who couldn't care less about El Nino may sit up and take notice when some-body mentions the North Atlantic Oscillation. Although it's less important on a global scale than ENSO, the NAO is a much bigger player in Europe's climate. Unlike El Nino, it's an atmospheric cycle that operates more or less independently of […]

The people who know El Nino best

In Spanish, El Nino means 'the male infant” or, when capitalized, the Christ child. Peruvians began applying the term to the ocean and atmosphere more than a century ago. Navy captain Camilo Carrillo noted in 1892 that local sailors referred to a periodic warming of the Pacific, which often occurred around Christmas, as El Nino. […]

The family name

Because therms far more to El Nino than a change in the ocean, the term is now popularly used to refer not only to the oceanic warming but also to the weather changes that go along with it Ditto for La Nina. However, scientists have to be more precise than this. Some argue over which […]


Drought is one weather extreme that’s defined not by what happens but by what doesn’t happen – namely, rain. It’s as if nature forgot that it was supposed to provide a certain amount of moisture each year. The meteorological spigots are shut down, and nobody can say just when they’ll be turned on again, although […]


Most weather events descend upon us. Floods rise up to meet us from below – sometimes quietly, sometimes ferociously. They're one of the few weather-related hazards that can be made far worse by the way we choose to live: where we pave the land, build houses, fell trees and dam rivers. And floods may be […]

Canyons and water: a dangerous combo

The lure of a slot canyon – narrow and serene, with walls that ascend far higher than the canyon's width – is hard for a serious hiker to resist Thousands traipse into these flash-flood factories each year unaware of the risk they face. A downpour in one spot can send water pouring into a slot […]

Heat waves and cold waves

They aren't the flashiest of villains, but hot and cold spells – when they're sufficiently intense and prolonged – are among the deadliest of all weather events. Everyone knows that it's risky for us warm-blooded humans to spend much time in temperatures far above or below our margins of comfort. Yet only in the past […]

Europe feels the heat

Records melted like ice cubes across Europe during the astonishing summer of 2003. Pulses of heat plagued much of the continent in June and July, but by far the worst occurred in the first two weeks of August. Many areas topped 35°C/95°F day after day, with nights often staying above 20°C/68°F. England saw its first […]

Other windstorms

“They call the wind Maria” or so a classic tune from a 1950s musical informs us. A few years earlier, the forecaster-protagonist of the 1941 novel Storm did just that (and perhaps inspired the song) by dubbing a particularly mean cyclone Maria. The fixedness of our earth's landscape helps to shape the wind into familiar […]

You say diablo, I say sirocco

A hot wind by any other name is just as enervating. The people of Los Angeles and San Francisco put up with occasional Santa Ana and diablo winds, respectively, that funnel down the canyons flanking these cities. Southern Europeans are familiar with a torrid desert wind that blows in from the Sahara or Middle East; […]

Coastal storms

Hurricanes are the most familiar of the storms that ravage coastlines, but they aren't necessarily the sturdiest. For all its immense power, a hurricane can be quite finicky. Should the sea surface be a touch too cool, or should a stiff wind tilt the central chimney of rising air a bit too much, the balance […]

Was it really the Perfect Storm?

Plucked from obscurity by a little-known writer, it gained fame on the best-seller lists. The coastal storm of October 31,1991, is now part of American pop culture as “The Perfect Storm” made famous by Sebastian Junger's 1997 book and the 2000 film of the same name. But did the event really live up to its […]

Most tropical cyclones spin up just north or south of the equator (but not on it), then move toward the west before angling poleward and eastward. Above are the names by region for tropical cyclones with winds of 118kph/74mph or more.

Hurricanes and tropical cyclones

The weather was probably quite tranquil on the Caribbean island of Barbados on the night of October 9, 1780: the calm before the storm. We know what it was like the next evening, thanks to Sir George Rodney. He and his fellow British colonials cowered in the government house, watching walls a metre thick crumble […]

Size matters…or does it?

Like the people the/re named after, hurricanes vary tremendously. They're actually little correlation between the size of a tropical cyclone and its strength. Some of the most destructive and powerful hurricanes are relatively small, and there have been numerous big, lumbering systems that packed little punch.The core of Hivrkane Andrew, which ravaged south Florida in […]

What’s in a hurricane name?

Most weather events come and go like nameless strangers, but each hurricane gets the human touch of a moniker all its own. Centuries ago, the worst hurricanes in Spanish-speaking areas were named after the saint's day on which they occurred. A more elaborate naming tradition started with Clement Wragge, a forecaster in Australia during the […]

South America’s stray hurricane

People in Brazil aren't used to hurricanes, to put it mildly. In fact, no hurricane had ever been reported there until 28 March 2004, when a mysterious system packing winds up to 137 km/hr (85 mph) swept onto the coast of Santa Catarina province. Forecasters from Brazil and from the US National Hurricane Centre had […]

Katrina, Rita, Wilma – and more

The degree to which climate change may be intensifying tropical cyclones across the world is a topic of spirited scientific discussion, but there's no debating the impacts seen in recent years. Five hurricanes struck or sideswiped the United States in 2004, with four of those slapping woebegone Florida. Meanwhile, a record 10 typhoons raked Japan. […]


Terrifying and mesmerizing at the same time, tornadoes have earned every inch of their fearsome reputation. They produce the strongest winds on the planet – close to 480kph/300mph. If that weren't enough, tornadoes can be astoundingly flaky. A tornado – often informally referred to as a twister – might last only seconds or churn for upwards […]

Tornado censors of 1900

For over fifty years, the word 'tornado' was taboo in US weather forecasts – ironically, because of early detection success. Military meteorologist J. P. Finley took it upon himself to issue the world's first large-scale tornado alerts in the 1880s. Using teletype reports from his own network of hundreds of observers scattered across the country, Finley […]


Countless folk tales have proclaimed that a region is protected from twisters by certain geographic features, such as a hill or river. The people of Topeka, Kansas, assumed they were being kept safe by a rise called Burnet Mound – that is, until the US city was ravaged by a killer twister on June 8,1966. […]


Hail isn't the most common weather hazard, but it can be one of nature's most efficient demolition tools. Anyone who's been caught in a hailstorm can tell you that the assault can really hurt. Hail kills an untold number of animals across the world each year and destroys many tonnes of crops. Over 200 people were […]

Sydney’s day of ice

It doesn't snow in Sydney to speak of, but Australia's biggest city makes up for it with occasional blizzards of hail. New Year's Day 1947 brought one such storm, with hail-stones the size of oranges. A more recent pummelling came on the evening of April 14, 1999 – quite late in the autumn for hail […]

The great hail war

If you're stuck in a car during a hailstorm, the racket may be enough to make you think you're in a war zone. Indeed, humans have treated hail as if it were a living, breathing enemy. Europeans of the 1800s fired rockets and cannons at hailstorms, hoping to either deflect the storm or break its […]


It s with very good reason that lightning evolved as a symbol of divinity in both the Bible and the Koran, as well as in Greek mythology and countless other religious and secular traditions. Few natural events are as familiar yet as awe-inspiring as a thunderstorm. The best estimate is that some 2000 thunderstorms are […]

Lightning strikes again – and again

If lightning never struck more than once in the same spot, the makers of lightning rods would have a tough time of it Since that day in June 1752 when Benjamin Franklin (inventor of the lightning rod) tapped into storm electricity with a kite and a key, we've known why tall objects tend to attract […]

What makes a storm green

Many cloud-watchers have noticed the peculiar green tint that sometimes appears in the heart of a strong thunderstorm. A popular explanation had it that hail or ice in the storm was refracting and absorbing the light to favour green wavelengths. In the mid-1990s, a pair of scientists took a spectrophotometer to Oklahoma and Florida, hunting […]


If you're reasonably warm and comfortable, then a thick cloak of fog can be one of the most sublime pleasures weather has to offer. Every hard edge in the landscape softens; a moist cocoon of cloud envelops both your physical and mental world, and everything around seems to shrink to a more manageable size. Fog […]

London’s killer smog

For some 300 years, coal-burning in London transformed the city's frequent fogs into sickening smogs. The Victorian taste for dark wallpaper was in part a clever way to disguise soot, and Dickens wrote of snowflake-sized soot particles. Still, nobody anticipated the disaster of December 4-8,1952, when a smog of epic proportions settled in beneath a […]

Putting fog to work

There aren't many deserts where the air feels soft and moist, as it does along the western fringes of Peru and Chile. Cold water that upwells along the coast keeps the air ultra-stable most of the time. Towns like Chungungo, Peru, may get less than 5cm/2in of rain a year, even as the chill ocean […]

Freezing rain and sleet

For the most part, winter ice doesn't do much more than inconvenience people for a few hours. Worldwide, it's far less common than snowfall, making it an unusual enough phenomenon to grab people's attention. The shimmering beauty of an ice storm, for example, offers a gratifying encounter with the work of Mother Nature while packing […]

Montreal’s icy onslaught

The sounds were inescapable: tree limbs cracking, power lines sparking, all of them crashing to the ground in various directions. From Monday to Friday, January 5-9,1998, the zone from northern New England to the St Lawrence Valley was locked in a strange and deadly weather pattern. While sub-freezing air held firm near the ground, wave […]


Nothing can lure the fun-loving child out of a grown adult more quickly than a snowstorm. Particularly in places where it doesn't fall very often, snow is a holiday-maker, an enforced interruption to our routine. Both kids and kids at heart fling snowballs; the more meditative among us stroll through a panorama of softened sound and […]

How to make an avalanche

The long-suffering towns of the Alps know the power of snow too well. For centuries, before control techniques were perfected, they were plagued by periodic avalanches. More than 2000 people died in 1618 when tons of snow slid into Plurs, Switzerland, and the Chiavenna Valley of Italy. Avalanches can strike anywhere there's enough snow: disastrous […]

New York’s blizzard of the ages

For North Americans, the winter of 1887-88 was an equal opportunity offender. The Midwest's worst snowstorm on record struck between January 12 and 14. Drifts topped 460cnV15ft and temperatures dropped as low as -47°C/-52°F. Some farmers in the Dakotas literally froze in their fields, and dozens of rural schoolchildren perished while walking home. Urbane New […]


It drizzles, it pours, it pelts. Rain falls on the just and the unjust, winners and losers alike. In some ways, rain is the planet's great equalizer, yet rain falls anything but equally around the globe. You could spend a hundred years in the middle of the Sahara and collect less rain than an Hawaiian […]

The real shape of rain

While songwriters have long thrown teardrops and raindrops into the same lyric for emotional effect, artists often use the former to illustrate the latter. Imagine the shock of a youngster if you told them that raindrops are actually shaped more like hamburger buns than teardrops. The tiniest cloud droplets are almost perfectly spherical, but as […]

This twenty-year analysis shows the average temperature for January across the globe.

Climate zones

Nobody really experiences climate per se. You can experience weather any time just by stepping outside, but climate is the average of sun, rain, snow, wind and other elements playing out over the long haul. This makes it an abstraction, built from the fragments of weather that caress or assault us. Even so, climate is […]

If warm air rises, why is Everest so cold?

You can't blame anyone for being confused. It's a fact of weather life that warm air rises and cold air sinks. Yet as anyone who's climbed a mountain knows, the air temperature usually goes down as you scale a peak. This seeming paradox has a subtle explanation. Warm air expands and cools as it rises, […]

The sunlight enters a raindrop, tiny variations in the entrance angle translate into a separation of hues as the light reflects and exits the drop. If conditions are right, the colours show up as a rainbow across the sky from the sun.

Sun, sky and colour: the optics of weather

Its a lazy summer evening by the lake. The Sun melts from its usual yellow into a blazing red as you watch it set over the water. As the bottom of the Sun noses below the horizon, the whole sphere seems to enlarge and flatten, as if somebody were stretching it against the land Finally, […]

The mysterious green flash

Jules Verne's 1882 novel Le Rayon vert (The Green Ray) focused on a rarely seen optical phenomenon. In the last moment of sunset at sea, the remaining glimmer of sun may turn “a green which no artist could ever obtain on his palette … If there is a green in Paradise, it cannot be but […]

Castles in the air

We're used to thinking of mirages as oases in the desert, surrounded by palm trees. In real life, our most likely encounter with a mirage is on the highway, where water may seem to shimmer in the distance. Mirages rely on a property of the atmosphere called refraction – the bending and spreading of light […]

The Shattuck Windmill Museum in Oklahoma is helping to preserve a legacy that goes back centuries.

Taking the weather’s pulse

According to rock legend Bob Dylan, you don't need a weatherman to know which way the wind is blowings He's got a point. Wet your finger, put it into the breeze, and you'll sense the wind's direction right away. You could do the same thing with a basic wind vane or, for that matter, with […]

How to read a weather map

There's method in the madness of your local TV weathercaster when he/she is rambling on about curved, studded lines hanging from a little red “L”. The fronts on a basic weather map were devised by Bergen School meteorologists early in the twentieth century. It took years for them to be accepted by scientists in much […]

Humidity: it’s all relative

What does '90 percent humidity” really mean? Try thinking of water vapour as something that cohabitates with dry air; water vapour becomes more prevalent as winds bring it in or lakes and oceans evaporate more of it The warmer the dry air is, the more water vapour can coexist with it, which is where the […]

Face to face with the jet stream

Among its myriad of influences, World War II took aviation to new heights. Fighter planes regularly soared above 8km/5 miles.There they found a strange, strong wind that blew at unheard-of speeds. One Nazi spy-plane reported 170-knot winds (310kph/195mph) before it crashed in the eastern Mediterranean. In November 1944, two US squadrons approaching Tokyo from the […]

A concept worth flushing

Everyone knows that the water in a toilet bowl flows in the opposite direction if you cross the equator ~ or does it? Charlatans in equatorial countries have been using this notion for years to make a fast buck and dazzle visitors. With a tour group in tow, they carry a bowl with a drain […]

This Hawaiian tree serves as a freakish testimony to the power of ever-present trade winds.

Where does the wind go?

Wind is the flywheel of the Sun's heat engine, the motion produced by raw solar energy as it reaches Earth. It sculpts our weather, as it forms clouds, fronts and countless other weather features out of thin air. Yet for a surprisingly long time, people didn't quite know what to make of the wind. Classical […]

Since air absorbs and disperses sunlight, point В gets a more intense dose than A.

The Sun and Earth

Consider the total solar eclipse – a thing of undeniable beauty. When the Moon passes before the Sun, all that remains visible for a few minutes is the shimmering corona. Perhaps even more remarkable than the sheer beauty of an eclipse is its sheer improbability. The Sun is far larger than the Moon, but it's […]

Forces behind the Northern and Southern Lights

The beautiful sky show known as aurora borealis (or australis, in the Southern Hemisphere) is, in fact, a manifestation of molecular violence. Aurorae are produced by the solar wind, a stream of charged particles from the Sun. Because Earth's magnetic field is a very good plasma shield, the solar wind usually flows around it much […]

Layers of the atmosphere

The sky is the very definition of vastness. When we take a boat to sea or find ourselves on a treeless plain, were reminded just how all-encompassing the sky can feel. Its easy to believe the atmosphere must go on forever, stretching outward and upward. Try this perspective, though: Earth as seen from the US […]

The weight of it all

Living in it as we do our whole lives, it's easy to forget that air is heavy stuff. All of the air that rests on top of an adult's head (an area of about 500 square centimetres or one-half square foot) weighs roughly 400 kg, or about half a tonne! Thankfully, our bodies are up […]

Crickets and other temperature scales

Even after the thermometer was invented, it wasn't obvious how to set its readings. Scientists bickered over which points on the scale should be tied to something in the natural world. Some favoured 'blood heat” or body temperature. In northern Europe, where thermometers were refined in the eighteenth century, people didn't expect air temperature to […]

Welcome to our atmosphere

An old pop song tells us that “love is like oxygen”. A politician concerned about the environment is accused of being “out in the ozone”. Computer programs that exist only in a promoters press releases are dubbed “vapourware”. Oxygen, ozone and water vapour are three of the most familiar ingredients in the life-sustaining soup we […]

The lighter side of humidity

Step off a plane in Miami or Calcutta and you may feel as if you've been hit by a tonne of hot, moist bricks. When air is extremely muggy, it feels thicker and heavier than usual. Actually, though, tropical air is less dense than its cold, dry counterpart when both are at the same air […]