How hot does Phoenix really get, and when is the best time of year to arrive?

The National Weather Service office for Phoenix issues extreme-heat warnings through the summer and publishes the climate records that show the pattern: a long run of days at or above 100°F, overnight lows that stay in the 80s and 90s°F in the hottest weeks, and the monsoon from mid-June to the end of September bringing humidity, dust storms and sudden flooding [1].

Life adapts: errands and exercise move to early morning, every building and car is air-conditioned, and the city and county run cooling centres and heat-safety programmes because heat illness is a real risk, especially for people who have just arrived and have not acclimatised [2] [3].

From late October to April the Valley is why people move here: dry, sunny and mild, with cold nights only in December and January. The state tourism office describes the seasons region by region, including the mountain towns such as Flagstaff that get real winters and snow two hours north [4]. If you can pick the date, land between October and March; your first summer is easier once your routines, house and car are set.