Phoenix has already hit 100 degrees. What does this early heat mean for summer?
On average, the Phoenix area experiences 111 days each year with temperatures reaching 100 degrees or higher, usually between May and October.
Phoenix reaches 100 degrees
For the first time in 2025, Phoenix reached 100 degrees. The Valley of the Sun typically sees around 111 days of reaching of at least 100 degrees or greater.
PHOENIX – It’s feeling hot, hot, hot in the Valley of the Sun, with the region marking its first 100-degree day of the year.
The official observation site at Phoenix Sky Harbor International Airport reported a high of 100 degrees on Thursday – about three weeks earlier than the typical first day of triple-digit temperatures, which usually arrives around May 2.
On average, the Phoenix area experiences 111 days each year with temperatures reaching 100 degrees or higher, usually between May and October.
While it’s a bit early to start racking up triple-digit days, records indicate it’s not unprecedented.
The earliest 100-degree day on record in Phoenix was March 26, 1988, but did not lead to a record-breaking streak of warmth.
Does that mean a very hot summer?
"Just because we’ve hit 100 degrees already doesn’t mean we’re automatically heading into another scorching summer," the National Weather Service office in Tempe, Arizona, said.
What kind of heat Arizona and much of the Southwest will endure this year depends heavily on how the upcoming monsoon season unfolds.
If the monsoon ends up being more active than average, it could help curb extreme heat by bringing increased cloud cover, thunderstorms and moisture to the region.
In an aerial view, the downtown skyline is seen during a heat wave on July 15, 2023, in Phoenix, Arizona.
(Photo by Brandon Bell/Getty Images / Getty Images)
"The strength and timing of the monsoon are critical," the NWS stated. "A robust monsoon pattern can knock down those extreme high temperatures that typically build up."
The official monsoon season runs from June 15 through Sept. 30, but delays in its arrival or weaker-than-normal activity can have a significant impact on summer temperatures.
For instance, a lackluster monsoon season in 2024 contributed to Phoenix setting multiple heat records, including the longest stretch of 100-degree days in the city’s history.
Without consistent cloud cover and rainfall, Phoenix recorded 111 consecutive days at or above 100 degrees, with several days climbing above 115 degrees.
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According to long-term outlooks produced by NOAA’s Climate Prediction Center, there are signs that monsoonal moisture will not be as distressed as in previous years, meaning that chances of breaking heat records may not be as high as they currently appear.
Outlooks from April through June show a tendency toward drier and warmer-than-average conditions to prevail, so while the spring and early summer may look hot, there is at least some hopefulness during the later summer months that the region will see some relief.
Bottom line, early 100-degree days are worth noting, but they don’t necessarily mean 2025 is on track for a record-breaking heat wave.
Precipitation outlook for June, July, August.
(NOAA)