The air masses over much of Europe are relatively similar to those in the United States but some differences do exist. The differences have much to do with the Atlantic Ocean that lies between the two continents allowing mA air to reach Europe. Prague is affected by more than one mir mass. The air masses that affect Prague are Continental Trpoical (cT),Continantal Polar (cP), Maritime Polar(mP), and Maritime Arctic(mA). mA air masses in the winter seaons become present as the air sweeps over Western Europe and down into the Mediterranean through a cyclonic system which often times leads to snow in Prague. In the summer months, mP air moves into Prague and is responsible for their typialy dry to moderate summers with the occasional thunderstorm. The cP air mass that moves into central Europe from northern Europe changes as it moves into Prague. During the summer this air mass is responsible for clear skies and good visibility along with cool nights and mornings. Although the temperatures feel cool, by midday it feels relatively warm.
OLD TOWN SQUARE IN THE SUMMER OLD TOWN SQUARE IN WINTER
This variability of the weather is caused mainly by the changeable location and magnitude of two main pressure centers: the Icelandic Low and the Azores High. Mainly during the warm middle of the year, it can generally be said that expansion of the high pressure projection into the territory causes warmer and drier temperatures, whereas the Icelandic Low manifests itself with a greater number of atmospheric fronts, which bring more clouds and precipitation.
Soucres:
http://www.tpub.com/content/aerographer/14312/css/14312_104.htm
http://www.czech.cz/en/66848-climate
