That's a common refrain from climate change deniers, and in the most basic sense, they are not wrong. Summer has always been hot in Phoenix.
But it's never been this hot.
Hundred-degree temperatures have already become routine this year in the Valley, meaning summer is here in full force. Forecasters were right when they predicted that the summer of 2025 wouldn't be as hot as the past two, each of which broke records. But it was hot as hell.
Statewide, Arizona experienced its third-hottest summer ever. In Phoenix, 2025 ranks as the fourth-hottest summer on record.
Many people have commented they thought this summer was rather "mild". This is what acclimation & recency bias does when considering the past couple summers. In fact, summer 2025 was the 3rd warmest on record (since 1895) for the state w/ most counties in the top 5. #azwx pic.twitter.com/o7NFnDeDdF
— NWS Phoenix (@NWSPhoenix) September 9, 2025
The scorching seasons are a recent phenomenon. According to data from the National Weather Service going back 100 years, nine of Phoenix's 10 hottest summers have all come this century.
In 1924, the average temperature across June, July and August was 89.1 degrees Fahrenheit. Last year, the average temperature over the same span was nearly 99 degrees. For that, we can thank climate change and the urban heat island effect, which have combined to make Phoenix the hottest city in America.
The average temperature across June, July and August in Phoenix has steadily risen over the past 100 years, according to data from the National Weather Service.
Illustration by Zach Buchanan
Here, in ascending order, are the 10 hottest summers in Phoenix history.
Hottest summers in Phoenix
10. 1981: 94.82 degrees
Ah, the Eighties! A time of weird music and weirder clothes. Unfortunately, the temperature didn't stay in the 80s this particular year, a true outlier for the decade. The next-hottest '80s summer came in 1989, with an average of 94.4 degrees.9. 2002: 94.85 degrees
Fun fact: The summer of 2002 doesn't rank in the top 10 for any individual month. But it was so consistently hot that year, it lands here as the seventh-hottest of all time.8. 2019: 94.91 degrees
This summer was another late bloomer — late swelterer? — starting off cool and ramping up to an average of 96.8 degrees in August, the sixth-hottest August in the last 100 years.7. 2007: 94.92 degrees
Another year with a blistering August, which averaged 96.2 degrees, the eighth-highest for that month. But 2007 leaps ahead of 2019 thanks to a slightly hotter (but still relatively mild) June that averaged 92.7 degrees.6. 2013: 95.07 degrees
Some years lull you into a false sense of security. Others, like 2013, kick you in the mouth immediately. Averaging 94.8 degrees, June 2013 was the fourth-hottest June on record.5. 2015: 95.11 degrees
This particular summer had a hot June, a hot August and a run-of-the-mill July, which averaged only 94.7, ranking 35th for that month.4. 2025: 96.26 degrees
If it feels like 2025 was a milder summer, that might be because the previous two years were so hot. This past summer was hot across the board, albeit not in ways that stood out historically. The 11th-hottest June in history was followed by the ninth-hottest July and the fifth-hottest August. Put it all together and it means there was little relief from the heat.3. 2020: 96.72 degrees
Well, if we were going to be locked inside for one summer, it might as well have been 2020. That July was the third-hottest on record, with an average of 98.9 degrees. August was the hottest August ever at 99.1 degrees.And then the world got better, right? Right?
