except for the southwestern province of asir, saudi arabia has a desert climate with very high day-time temperatures and a sharp temperature drop at night. average summer temperatures are around , but can be as high as . in the winter the temperature rarely drops below . in the spring and autumn the heat is temperate, temperatures average around . annual rainfall is extremely low. the asir region differs in that it is influenced by the indian ocean monsoons, usually occurring between october and march. an average of of rainfall occurs during this period, which is about 60 percent of the annual precipitation.