The climate in the United Arab Emirates is sub-tropical and arid. During summer (April to September) the weather is hot (around 50 degrees C) and extremely humid. At other times the humidity is less and the temperature generally ranges from 20-35 degrees C, with an average night time temperature of -15 degrees C. Rainfall is infrequent and usually occurs between November and March, with an average annual rainfall of 152mm (6 in.). There can be occasional sandstorms from the desert and some winter mornings bring fog, although this usually dissipates fairly quickly.