<P> Compared to areas located in the higher middle latitudes, parts of western Europe have mild winters and higher annual temperatures (though summers are cooler than locations at the same latitude). Berlin, Germany; Calgary, Canada; and Irkutsk, in the Asian part of Russia, lie on around the same latitude; January temperatures in Berlin average around 8 ° C (15 ° F) higher than those in Calgary (although Calgary sits 1200m higher in altitude), and they are almost 22 ° C (40 ° F) higher than average temperatures in Irkutsk . This difference is even larger on the northern part of the continent; the January average in Brønnøysund, Norway, is almost 15 ° C warmer than the January average in Nome, Alaska, both towns are situated upwind on the west coast of the continents at 65 ° N, and as much as 42 ° C warmer than the January average in Yakutsk which is actually slightly further south . Further south the oceanic climate of Europe compares thermally to North America, at around 48 ° N Rennes, France has about an equal average temperature throughout the year to Seattle, Washington, although the latter has drier summers with much wetter winters . </P> <P> The lack of precipitation found along the eastern coasts of Europe is due to the westerly wind flow which dominates across the continent . A bulk of the precipitation across the Alps falls between March and December . The wet season in lands bordering the Mediterranean Sea lasts from October through March, with November and December typically the wettest months . For example, the monthly rainfall at Athens ranges from 6 mm (July) during their dry season to 71 mm (December) during their wet season . Summer rainfall across the continent evaporates completely into the warm atmosphere, leaving winter precipitation to be the source of groundwater for Europe . Places with significant impact by acid rain across the continent include most of eastern Europe from Poland northward into Scandinavia . </P> <P> The European Monsoon (more commonly known as the Return of the Westerlies) is the result of a resurgence of westerly winds from the Atlantic, where they become loaded with wind and rain . Rather than a traditional monsoon, where warm seas fuel precipitation and storms, they are more cyclonic low - pressure systems that travel along the section of the gulfstream . These Westerly winds are a common phenomenon during the European winter, but they ease as Spring approaches in late March and through April and May . The winds pick up again in June, which is why this phenomenon is also known as "the return of the westerlies". </P> <P> The rain usually arrives in two waves, at the beginning of June and again in mid to late June . These storms generally feature significantly lower than average temperatures, fierce rain or hail, thunder and strong winds . The Return of the Westerlies affects Europe's Northern Atlantic coastline, such as Ireland, Great Britain, the Benelux countries, Western Germany, Northern France and parts of Scandinavia . </P>

Which two factors most influence europe's climate and vegetation