August knocked July out as Tucson's hottest month ever, as the longest and most brutal heat wave in recent memory here continued.
Summer 2020 also won the dubious distinction of being Tucson's hottest summer since climate records started being kept here in 1897, the National Weather Service said Monday.
Through Sunday, August's average daily temperature was 92.3 degrees. That's nearly a full degree warmer than July's average daily temperature of 91.5 degrees, the weather service said. That average daily temperature had made July the hottest month ever recorded in Tucson.
This August's average daily temperature so far has been 7.1 degrees above August's normal average daily temperature of 85.2 degrees. It stands at more than 2 degrees above the previous August record of 90.2 degrees, set in 1994.
While Monday's cooler weather will definitely lower August's monthly average temperature, it won't lower it enough to put this month's average below July's, said Carl Serniglia, a weather service meteorologist.
Unlike many summer seasons, this August's scorching days were a bigger factor in setting the record than warm nights, whose temperatures are propped up by the urban heat island effect. The heat island effect is caused by the proliferation of pavement and buildings that absorb the sun's heat during daylight hours and radiate them out at night.
August's average daily high temperature was 105.7 degrees, more than eight degrees above the normal for August of 97.4 degrees. The average low was 78.9, more than five degrees above the normal August low temperature of 73.3 degrees.
"It was awful," Serniglia said of August's heat. "We had 4 days in August of 110 degrees or hotter and 26 days of 100 or better."
Specifics on the record summer 2020 heat will be available on Tuesday, weather service officials said.
The weather service has blamed this summer's unrelenting heat on a high pressure system that hung over this state and neighboring New Mexico much longer than normal, breaking up only late last week when monsoon rains finally arrived and temperatures dropped sharply.
Without conducting more research, scientists generally don't like to attribute short-term weather fluctuations to long-term climate change caused by greenhouse gas emissions. But many climate scientists have said that the number and intensity of extreme heat waves is likely to increase over time due to longer-term warming patterns.
