The monsoon season officially begins on June 15 and runs until September 30.
During that time, thunderstorms can often form in the heat of the day, bringing heavy rain, lightning, damaging winds, dust storms, and flooding.
Not all monsoons are the same, though. Some years, our monsoon season is hot and dry, and other years are not as hot and very rainy.
So, how will Monsoon 2025 play out?
The NOAA Climate Prediction Center has odds favoring a wetter-than-normal monsoon across Arizona this year.
Wetter summers often follow dry winters, and this past winter was one of the driest on record across Arizona.
Phoenix only picked up 0.03 inches of rain during the months of December, January and February, marking the third driest winter on record.
We also recorded the second-longest dry streak ever at Phoenix Sky Harbor with 159 days in a row without measurable rain.
Tropical activity in the eastern Pacific Ocean could also influence our monsoon by “beefing up” our moisture flow from the south.
In fact, even before the monsoon season started, remnant moisture from Tropical Storm Alvin led to the wettest start to June ever recorded in Phoenix.
Sky Harbor picked up 0.24 inches of rain on June 1, 2025, breaking the old record of 0.02 inches set on that date in 1914.
That’s significant since the overall average rainfall for the entire month of June is a measly 0.02 inches!
But what’s considered a “normal” amount of monsoon rain has changed a lot in the past 50 years.
Every 10 years, new normals are calculated based on a rolling 30-year average. Our latest update came in 2021, giving us a new average that is based on rainfall data from 1991 to 2020.
This new normal showed an average rainfall in Phoenix for the monsoon season of 2.43 inches of rain. That’s more than a quarter of an inch drier than the previous average, which is a big difference here in the desert!
This shows climate change’s impact on our monsoon weather in Phoenix. It’s not only trending hotter as our urban heat island expands, but also drier as our climate changes.
This year’s monsoon season is expected to be wetter than normal, but that is wetter than the new normal of 2.43 inches of rain.
The Climate Prediction Center also has odds favoring a hotter-than-normal monsoon in the Valley and all across the Southwest.
It likely won’t be as hot as last year’s record-shattering summer, though.
With very little monsoon rain last year, the heat dominated. Monsoon 2024 tied for the seventh driest on record in Phoenix with less than three-quarters of an inch of rain.
This monsoon should be a lot wetter and not as hot as last year.
So, count on ABC15 to keep you ahead of the storms. We’ll have updates on-air, online, on social media, and on all of our streaming channels.
