In Phoenix, nine of the first 22 days of June have been 110°F (43°C) or hotter, including the last five consecutive days.

And the number of days each year above 110°F continues to climb there.

If the current trend in greenhouse gas emissions continues, there may be as many as 70 days each year hotter than 110°F in Phoenix.

The low in Phoenix on Monday was 90°F (32°C), which is the earliest in the year the low temperature has not dropped below 90°F. The hotter nights do not allow the body to recover from the heat stress of the daytime, increasing the risk of heat-related illnesses