With its arid climate, Phoenix has been ranked the hottest city in the United States, and one of the hottest in the world. The temperature in Phoenix registers at least 100°F (38°C) or more on an average of 90 days of the year, mostly between June and September, which are the summer months.Most days are sunny and hot, and rainfall is scarce, although there are thunderstorms sometimes between July and September, caused by humid air blowing in from the Gulf of California. Winters bring mild, sunny days, with occasional fog. Snow is rare, but has been recorded; frost is frequent in the winter months.
