The country is a sandy, riverless desert interspersed with small hills. Vegetation is sparse. Kuwait's climate is typical of the region. Summer (April-October) temperatures often exceed 120°F, although daytime temperatures of 110-115°F are more common. Mean annual rainfall is 45 inches and occurs mostly during December and January. Short autumn and spring seasons (November, February, and March) are delightful. During winter (December and January), clear, sunny days are common, but it is often cold enough to require a light winter coat in the mornings and evenings. In the early morning the frost point is occasionally reached. Sand and dust storms occur throughout the year, especially between March and August. Periods of high humidity occur, but during the hottest months (June, July, and August), humidity levels usually remain very low.