Weather: Democratic Republic of the Congo, Central African Republic

At the heart of equatorial Africa, the Democratic Republic of the Congo (formerly Zaire) has one of the more dependable climatic regimes of the continent. The ITCZ pulls wet, thundery weather to the north from March to November and to the south from December to February. In between, the central Congo basin, including Mbandaka (perched directly […]

Weather: Cameroon, Congo, Gabon, Principe, Sao Tome

This small, spectacular country lies at the crossroads of several African weather regimes. Few places can out-drench Cameroon's coastal delta, where moist southwesterlies are forced upward by Cameroon Mountain and neighbouring peaks to produce one of the world's wettest climates. Debundscha's annual average is over 1000mm/390in, and the coast is soaked from March to November. […]

Weather: Botswana

For a country that's half desert, Botswana has a surprisingly agreeable climate. Sunshine is ample year round, from the driest reaches of the south to the wildlife-studded swamps of the Okavango Delta. The stretch from the Delta to Francistown is the wettest part of the country, but even during the wet season (October–March) thunderstorms arrive […]

Weather: Africa

More than any other continent, Africa is swept by the back-and-forth migration of meteorology's equator. Africans watch the globe-straddling intertropical convergence zone (ITCZ) as intently as a day trader watches stocks. As the ITCZ sloshes north and south over its annual cycle, it brings much of Africa its only period of annual rainfall. The dry-season/wet-season […]

Weather: Yemen

Don't expect a rainforest here, but the climate of Yemen does have its moist side. Every summer, a powerful low-level jet stream arcs from Somalia toward India. As the strong flow approaches Yemen's soaring western highlands, it can trigger substantial rains and thunderstorms. The high terrain picks up other moisture through the rest of the […]

Weather: Syria

Syria epitomizes Middle Eastern climate, with a Mediterranean wet-winter regime on the coast and a desert that spans most of the country east of a narrow strip of coastal mountains. Damascus is part of the Fertile Crescent, a transition zone near the Lebanon border that gets just enough moisture to keep the desert at arm's […]

Weather: Saudi Arabia, Bahrain, Iraq, Kuwait, Qatar, United Arab Emirates

With the world's largest expanse of sand at its heart, Saudi Arabia lives up to its reputation for dust and heat – at least between May and October – although the summer mode may arrive and depart a little ahead or behind schedule. The Arabian peninsula slopes eastward from a substantial rise near the west coast. […]

Weather: Oman

Wrapped around the eastern end of the Arabian peninsula, Oman is influenced by both the Arabian Sea and Persian Gulf. The nation's most populated area, along the Gulf of Oman coast, offers truly world-class sultriness. From May through September, the coastal strip is more hot and humid than Miami ever gets. Nights regularly hang above […]

Weather: Lebanon

Thanks in large part to its formidable mountains – some of which rise to 2500m/8200ft – Lebanon is one of the most well-watered spots in the Middle East. The mountains get enough snow for skiing in winter and can offer temperatures as low as the freezing point in summer. Even the coastal hills get 5 […]

Weather: Jordan

Despite its location less than 160km/100 miles to the east of the Mediterranean, Jordan is a dry land. Only the western hills get an appreciable amount of moisture – as much as 800mm/32in in a few spots – though blustery showers and storms skim the eastern deserts a few times each winter. As in neighbouring […]

Weather: Israel

For its size, Israel boasts unusually varied weather. Like its neighbours to the north, it has a Mediterranean coastal zone that gets regular winter rains. Annual amounts trend downward as you move south from the Haifa area (which gets around 630mm/25in, with a couple of soggy days every winter week) toward the Egyptian border (which […]

Weather: Iran

Ringed by high ridges, Iran has a mountain-and-plateau climate that belies its location next to two major bodies of water. The cold Asian high dominates in winter, but as it waxes and wanes, temperatures across parts of the interior may shoot above 16°C/60°F, or drop below –18°C/0°F. Mediterranean depressions arrive about once a week on […]

Weather: Middle East

A crossroads of culture and faith for millennia, the Middle East is also a place where giant weather regimes rub shoulders. Cold high pressure centred in Siberia pushes its way into the region each winter, which can be a surprisingly chilly season in the heart of the Middle East. Some of Iran's mountains remain snow-capped […]

Weather: European holiday islands

Most of what you need to know about the weather on the islands between Europe and Africa is summed up in the name of the sea that holds them. The Mediterranean's world-famous climate plays out on all of its islands through variations on a familiar theme: warm-to-hot summers that are bone-dry, and mild winters with […]

Weather: Western Balkans and vicinity

The western Balkans are a laboratory for weather extremes. Conditions can vary in striking fashion across small distances from coast to nearby peak, even from valley to valley. The Dinaric ridge runs parallel to the Adriatic Sea across western Serbia and north along the border between Croatia and Bosnia/Herzegovina. Mediterranean lows slam moisture against the […]

Weather: United Kingdom

You're never far from the ocean when you're in the United Kingdom. That fact tells you a lot – though hardly everything – about British weather. The climate here feels undeniably moist, yet the rain is by no means constant. Most of England gets measurable moisture not quite every other day, often amounting to little more […]

Weather: Ukraine

Like southern Canada, the Ukraine experiences summers warm enough to allow grains to thrive despite the high latitude. Even in Kiev, toward Ukraine's northern border, high temperatures average 22°C/72°F, or better, for more than three months of the year. Summer storms usually drop enough rain to keep crops healthy (although drought is always a concern), […]

Weather: Turkey

You can find bitter cold, scorching heat, damp gloom and brilliant sunshine within the borders of Turkey's uncommonly varied climate. The rugged west and south coasts are firmly Mediterranean. Here, the rains virtually cease from June through September but can be heavy in the cool winter. Along the coastal arc from Izmir through Antalya to […]

Weather: Switzerland

Geography has everything to do with the weather in this very mountainous country, especially across the Alps that dominate the country's southern half. The north slopes of the Alps are prone to the same cold waves that put Germany on ice. Meanwhile, south slopes are exposed to Mediterranean flow that's often balmy but laden with […]

Weather: Sweden

Although Sweden extends across nearly as much latitude as Norway, its north–south sweep is on the east side of Scandinavia's mountain corridor rather than the west side. That makes all the difference. With the mountains largely closing the door to Atlantic flow – though it's left ajar in places – Sweden runs distinctly colder and […]

Weather: Spain

It may be joined at its shoulder to Europe, but meteorologically speaking, Spain has little to do with the rest of the continent. The Iberian Peninsula goes its own way weatherwise, generating its own pools of cold air in winter and dry-roasting on its own in summer. Even if it were as pancake-flat as The […]

Weather: Slovakia

Slovakia's climate is split by the mountain ranges at its heart. The Danube lowland across the southwest is the nation's warm spot. Enough moisture trickles up from the Mediterranean so that many days in July and August feel a touch humid across the plains and on the Danube (where Bratislava and Vienna share a similar climate). […]

Weather: Romania, Moldova

Much like Bulgaria to its south, Romania has a four-season climate modulated by extensive highlands. Except for the highest parts of the Carpathians, most of the country will reach 26°C/79°F on a typical mid-summer day. Humidity is highest along the broad Danube valley. The warm season is the wetter time across the heart of Romania, but […]

Weather: Portugal

Flanking the west coast of the Iberian Peninsula, Portugal meets and greets Atlantic storm systems throughout the winter months, intercepting much of the rain before it can reach the plain or anywhere else in Spain. The mountains in the northern half of Portugal accentuate this effect. Some northern stations get as much winter rain as […]

Weather: Poland

As spacious as it is, Poland doesn't have much in the way of dramatic climate variations from place to place. What varies most is the weather itself, from day to day and season to season. The country isn't quite as mercurial as Russia when it comes to temperatures, but Polish weather can surprise a visitor […]

Weather: Norway

The Norway of picture books isn't so much a region as a ribbon, wrapping from southwest to northeast around more than 1600km/1000 miles of coastline. Off the west coast lies some of the world's warmest high-latitude water. This part of the Atlantic basin never freezes, even during weeks of winter darkness. The ocean currents that […]

Weather: The Netherlands

It's ironic that two of The Netherlands' most famous icons – its dikes and windmills – call to mind the image of a windy, waterlogged nation. True, it rains with regularity here, but no spot averages more than 1000mm/39in a year. That's below the norm in Wales and much less than on the west coasts […]

Weather: Lithuania, Belarus

Most of Lithuania is only a few hours' drive from the Baltic coast, but the inner parts of this country – including the touristed areas of Vilnius and Trakai – experience more of a dramatic change from summer to winter than their closeness to the sea might suggest. Winters are cold nationwide, though distinctly less […]

Weather: Latvia, Estonia

Scandinavians will feel at home with the climate of Latvia and its northern neighbour, Estonia. Both countries adjoin the Baltic Sea, with a west coast wrapping around the Gulf of Riga. Proximity to water gives these countries a cool, humid regime year round. Winter temperatures are relatively mild for the latitude – no colder, on […]

Weather: Italy

San Marino | Vatican City The cradle of the Renaissance was also the location where weather observing as we know it evolved, thanks to the efforts of Torricelli, Galileo and other Italian scientists and inventors. There is plenty to observe weatherwise across this varied country. Jutting into the sea, Italy is a sitting duck for […]

Weather: Ireland

Ireland is less likely than the UK to surprise visitors with unexpected weather. Positioned further into the Atlantic, the Emerald Isle has a more uniform temperature regime than the UK, and over 50 percent more rain as a whole. Cold snaps tend to lose their punch by the time they make it across the sea […]

Weather: Iceland

It may not quite live up to its name, but Iceland is indeed a chilly place. Reykjavik is the world's northernmost capital (aside from Nuuk, Greenland), and it may also be the one with the coldest summers: in July, the average highs stay below 14°C/57°F. Warm ocean currents and the most favoured track of North Atlantic […]

Weather: Hungary

The open fields of the Great Hungarian Plain cultivate one of Europe's most vivid four-season climates: visitors from the American Midwest will feel at home. Summers are bathed in sunshine, with frequent afternoon and evening thunderstorms rolling across the prairie. Especially in the Danube valley, there's often enough moisture in the air for it to feel […]

Weather: Greenland

Most of this semi-independent Danish province is slathered by the Northern Hemisphere's largest sheet of ice, rising more than 3300m/10,000ft high at its centre. By and large, tourists wisely stick to Greenland's coasts, where summers are chilly but bright. During the peak June-to-August travel season, average highs remain above 6°C/40°F along the entire west coast, […]

Weather: Greece

It's hard to summarize the climate in a land with 2000 islands, high mountain peaks, and exposure to air masses that range from sub-tropical to polar. Nearly all of Greece is ruled by a Mediterranean regime, which means that precipitation is focused in the cool season. Summers are virtually rain-free: the best chance for a […]

Weather: Germany

Although Germany covers a fair amount of north–south distance – from the Alps to the northern seas – the weather doesn't vary a tremendous amount across this reach. There's no more than about 5°C/8°F difference in the average temperatures of Germany's major cities. As is the case elsewhere in northwest Europe, it rains or snows […]

Weather: France

Although it's not an island like its neighbour across the English Channel, France is bordered on three sides by water. The Atlantic and Mediterranean help to moderate the temperature swings that otherwise might occur at France's latitude. The ragged northwest coast of Brittany and Normandy has a climate not too dissimilar to much of Great […]

How does weather shape France’s wines?

More and more wine is being grown in places with hot Mediterranean-style climates, Australia and California among them. But France's unique blend of landscape and weather – its terroir – has nurtured the grape for centuries. Experts have found that wine grows best in regions with cool winters that are a little above freezing and […]

Weather: Finland

Lake-strewn Finland has a maritime feel, although the huge air masses that build over continental Russia are never too distant. The ebb and flow between these influences is the main driver of Finnish climate. The Atlantic and the high latitude keep things relatively cool in summer, with few big temperature differences across the country. It […]

Weather: Denmark

Except for its border between Jutland and Germany, Denmark is essentially an island nation with a climate to match. As in The Netherlands and southern Sweden, you can expect some form of light precipitation almost every other day year-round, although the rain or snow is seldom very heavy. Atlantic gales pound the west coast of Jutland […]

Weather: Czech Republic

The mountains that encircle much of the Czech Republic help to shield it from the coldest of the air that flows west from Russia. Nonetheless, the country tends to remain on the chilly side during the winter throughout the lowlands, and colder still in the mountains. A dusting of snow may fall every 2 or […]

Weather: Bulgaria

Two mountain ranges and two broad valleys make up the setting for Bulgaria's four-season climate. The Balkans run east–west through the nation's heart, and they shield the southern lowlands somewhat from outbreaks of winter cold. Along the southern border, the Rhodope Mountains help prevent the hot, humid air of Greece from sweeping northward. It's still […]

Weather: Belgium, Luxembourg

Belgium is a land of gentle transitions meteorologically as well as culturally. The weather of Flanders is very similar to that of the adjacent Netherlands: cool winters, milder summers (especially as you move inland) and, in all seasons, frequent – through seldom intense – rain. As you move south into Wallonia, the climate becomes a little more […]

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

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 […]

Floods

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 […]