Mediterranean climate: Encyclopedia II - Mediterranean climate - Cause

Mediterranean climate - Cause

In most places with Mediterranean climates, rainfall results almost entirely from the procession of the westerly zone of frontal storms during the low-sun season; during the summer, the subtropical high pressure zone dominates the seasonal weather, preventing rainfall by inhibiting rainstorms from forming.

This summer-dry, winter-wet rainfall pattern is extremely rare, and is only found in a small number of regions on Earth. The greatest concentration of Mediterranean climates is encountered immediately poleward of the great dry belt of subtropical deserts but equatorward of the zone of maritime temperate or oceanic climates. They are never on the east coasts of continents.

Adapted from the Wikipedia article "Cause", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki