The weather in Yemen changes from area to area according to the changing geographical patterns. The four seasons, however, overlap to appear as if they were two, summer, and winter. The summer spans the period from April to September. Summer is moderate in the mountain area and hot with high humidity on the coastal areas, and the Islands. The winter, on the other hand, spans the period from October to March. It is moderately cold in the mountains and moderate in the islands and coastal areas.
In the coastal area (the Tihamah region), the climate is primarily dry and hot with an annual rainfall of about 229mm (9in). This region is prone to severe sandstorms and maximum daytime temperature range from 32°C in winter to over 40°C in summer.
The highland areas boast a mild, temperate climate with pleasantly cool winters. Temperatures range from 21.7°C in June to 13.9°C in January. Highland rainfall varies from about 406mm (16in) to 762mm (30in).
Two periods of increased rainfall are linked with the eastern and western monsoons; the first of these arrives in April/May and the second in July to September. Most of the rain falls on the western mountains.