Moldova's climate is moderately continental: the summers are warm and long, with temperatures averaging about 20°C, and the winters are relatively mild and dry, with January temperatures averaging -4°C. Annual rainfall, which ranges from around 600 millimeters in the north to 400 millimeters in the south, can vary greatly; long dry spells are not unusual. The heaviest rainfall occurs in early summer and again in October; heavy showers and thunderstorms are common. Because of the irregular terrain, heavy summer rains often cause erosion and river silting.Required clothing Mediumweights, heavy topcoat and overshoes for winter; lightweights for summer. A light raincoat is useful.