Saudi Arabia satellite image-Ecoregions as delineated by the WWF. The yellow line encloses the ecoregions – Arabian Desert, East Sahero-Arabian xeric shrublands and two other smaller desert areas.[263]
Saudi Arabia's Köppen climate classification map[264] is based on native vegetation, temperature, precipitation and their seasonality.
BWh Hot desert
BWk Cold desert
BSh Hot semi-arid
BSk Cold semi-arid
Except for the southwestern province of Asir, Saudi Arabia has a desert climate with extremely high day-time temperatures and a sharp temperature drop at night. Average summer temperatures are around 113 °F (45 °C), but can be as high as 129 °F (54 °C). In the winter the temperature rarely drops below 32 °F (0 °C). In the spring and autumn the heat is temperate, temperatures average around 84 °F (29 °C). 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 300 mm (12 in) of rainfall occurs during this period, that is about 60% of the annual precipitation.