Climate in Tucson

The most obvious difference of climate from most other inhabited regions is the hot and sunny climate. This difference is a major contributing factor to a rate of skin cancer that is at least 3 times higher than in more northerly regions. Media reports heat related deaths increasing among illegal immigrants in and around Tucson. Heatstroke related deaths have been recorded since 1999 in the Pima County Area.

The monsoon can begin any time from mid-June to late July, with an average start date around July 3. It typically continues through August and sometimes into September. Winters in Tucson are mild relative to other parts of the United States. Daytime highs in the winter range between 64 and 75 °F (18 and 24 °C), with overnight lows between 30 and 44 °F (−1 and 7 °C). Tucson typically averages one hard freeze per winter season, with temperatures dipping to the mid or low-20s (−7 to −4 °C), but this is typically limited to only a very few nights