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 fairly dependably in each month of the year.
The regional differences that do exist across Germany can be rather counter-intuitive. For instance, you might expect the coldest winters and the wettest summers to be along the northern tier, by the Baltic and North Seas. In fact, both accolades belong to the far south. Winter's coldest air masses arrive on northeast winds that butt up against the German Alps. This gives Bavaria long stretches of chilly, overcast gloom, sometimes paired with light snow or cold rain and heavier snow at elevation. On average, there's fog on as many as 1 out of 3 winter days across southern Germany. Compensating for these gloomy spells are occasional bright, mild days, forged as dry, southerly fohn winds descend from the Alps, especially near the beginning and end of winter. Across northern Germany, the mild spells are more likely to be furnished by moist winds off the Atlantic, which can exceed hurricane force in the strongest gales along the North Sea. Germany's winter temperatures average only a few degrees lower than those in France, but the occasional Siberian front can send temperatures down much further, well below –20°C/–4°F at times across most of the country.
In common with the rest of central Europe, summer in Germany can be a fickle experience: often spectacular, sometimes miserable. The uncertainty starts in the unsettled spring, which is prone to bouts of cool, showery weather interspersed with glorious warm-ups. Folk wisdom has it that a chilly, wet period of “sheep cold” sets in around the middle of June. As the heart of Europe heats up with the approach of the summer solstice, cool, damp air can indeed be drawn into Germany from the still-chilly waters of the North and Baltic Seas. By July, warm weather becomes more dependable. In fact, it's sometimes very hot. Readings above 35°C/95°F have occurred at most of the lower elevations, and 30°C/86°F is not uncommon. Germany sees a good amount of thunderstorm action in the summer, with hail especially likely across the southern half. (Munich is infamous for its powerful storms; see “Hail”, p.74.) The thunder abates quickly in September and October, when morning fog may be the only deterrent to otherwise gorgeous autumn weather. By November, you're likely to find cloudy, chilly conditions setting in most everywhere.
Overall, the north and west slopes of major mountain ranges and hilly regions tend to get more rainfall than the eastern sides. Germany's wettest corner is the Black Forest area, which averages more than 1000mm/39in. The east is the driest; parts of the Elbe Valley may get only 500mm/20in in a typical year.