July was extremely hot, even for Phoenix. With a monthly average temperature of 101.1 degrees, it was the second-hottest month in Phoenix history.
The only month hotter than July of 2024 in Phoenix was July of 2023. Last year, the average temperature for the month of July was a record-shattering 102.7 degrees. According to the National Weather Service, a normal average temperature for the month of July at Sky Harbor Airport would be 95.5 degrees.
Last year in July, daytime high temperatures reached 110 degrees or hotter on all but one day. This July, once again, almost every day surpassed 110. The handful of days that were cooler over the past month all rose to 109.
But it wasn’t just extreme daytime highs that made this July’s average temperature so hot. Overnight lows never dropped out of the 90s for most of the past month.
“The day’s climb toward a high temperature is already several steps up by the time you wake up,” said Randy Cerveny, a professor of geographical sciences at ASU and Rapporteur on Extreme Records for the United Nations World Meteorological Organization.
Cerveny said there’s an exponential trend in the number of 90-degree nights Phoenix records each summer. Since the 1990s, Phoenix has averaged seven days per year with low temperatures in the 90s. As of July 31, Phoenix has had 25 nights in the 90s so far this year.
Cerveny said that’s troubling.
“Carbon dioxide traps in the heat that’s collected during the day and therefore we get hotter during the night, so it’s one of the clear indications that we have that climate change is going on,” Cerveny said.
This July’s near-record heat followed an extremely hot June. Phoenix’s average temperature was 97 degrees throughout June – the hottest temperature ever recorded for that month.
Cerveny said August could bring some relief to the Phoenix area if monsoon storms materialize to bring temperatures down.
EDITOR'S NOTE: This story has been updated to correct the spelling of Randy Cerveny's name.
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