Cyprus is for the most part dry and sunny. The warm currents of the Mediterranean ensure mild winters but bring humidity to the coastal area in the summer, when the central plain is hot and dry. On the hills, daily sunshine is interrupted only occasionally by a wet period rarely lasting more than a week. The mean annual temperature is about 20° C (68° F ). A cool, rainy season lasts from November to March. In winter, snow covers the higher peaks of the Troodos; elsewhere the temperature seldom falls below freezing, and conditions are mild and bracing. Rainfall is erratic and varies greatly in different parts of the island. The annual average precipitation ranges from below 30 cm (12 in) in the west-central lowlands to more than 114 cm (45 in) in the higher parts of the southern massif. The main agricultural areas receive rainfall of from 30 to 40 cm (12–16 in) annually. Earthquakes are not uncommon.