New Phoenix fall forecast released: What to know

With less than a month until the first official day of fall, that time of the year when the edge finally comes off the Arizona heat. But don’t get too excited — according to the National Weather Service, Phoenix should see hotter and drier conditions than usual this autumn.

“We are translating our warm and dry summer … into the fall too,” said National Weather Service meteorologist Tom Frieders.

The NWS’s Climate Prediction Center projects above-average temperatures and below-average rainfall across the Valley for September, October and November. The northeastern corner of the state has even stronger chances of higher-than-normal temperatures.


From September through November, the Valley typically averages just less than 70 degrees with a little more than two inches of rainfall, according to the National Weather Service. Though recent monsoon activity has brought welcome rainfall to Phoenix, the NWS projects the Valley to have slightly below normal rainfall this fall.


While fall in Phoenix is rarely all that cool, recent years have set new extremes. Last year saw the hottest September and October on record, according to a recent NWS report. That same report named last September, October and November the driest on record. Phoenix notably went without rain for 159 straight days, a streak that started this time last year and lasted well into 2025.

Last year, the increased temperatures led Phoenix to close trails in late September. Hotter temperatures also increase wildfire risks. The dry conditions affect water resources. Today, the Salt River Project’s reservoirs are only 55% filled compared to 81% on the same day last year, according to SRP’s daily water report.

The Old Farmer’s Almanac also predicts a warm, dry fall for most of Arizona. “Expect warm to hot days with scattered storms early, then sunny and very warm through month’s end,” the publication said in its Desert Southwest forecast for September. For October, it said to “expect a mix of sunny and rainy periods, with mild to warm temperatures throughout.”

It is too early to say if any records will be broken, Frieders said. But the possibility of that is something for which the NWS is always on alert.