Arizona’s monsoon season began Monday, and Phoenix got a quick taste of it before dawn. Passing showers and storms moved through the Southwest Valley and into the Southeast Valley, then faded early in the morning, leaving the Valley with rain in the air and heat still in charge.
The new season runs from June 15 to September 30, and Monday’s forecast showed why it matters. Phoenix had about a 20% chance of storms by evening, with more scattered showers and thunderstorms possible later in Arizona and into the night, while the city stayed on track for a high near 108 degrees.
That mix is the monsoon in a single day: brief rain, fast-moving storms and not much relief from the heat. Forecasters said storms developing over the higher elevations of northern and eastern Arizona could drift down the mountainsides toward the Valley, where a few passing cells could bring gusty conditions, patchy blowing dust and lightning.
Captain Ashley Losch said most Valley residents know how quickly and furiously storms can move in and out, bringing strong winds, dust, rain and flash flooding. She also warned that the storms can interrupt services such as water, power and gas. For people trying to make plans around the weather, that is the part of monsoon season that matters most: a storm can arrive, create problems and disappear before the sky looks threatening again.
At the same time, the heat did not back off. Overnight lows around the Valley were expected to slip only to the mid 80s to near 90, and Phoenix was forecast to climb to 110 on Tuesday and 109 on Wednesday. There was also a 10% chance of showers on Thursday, but the city was still expected to stay around 107 on Thursday and Friday before easing to near 105 over the weekend.
Parts of Arizona were under flash flood warnings as the weather system moved through the state, and an extreme heat warning remained in place for parts of the Grand Canyon. The immediate story for Phoenix is not a soaking rain or a sudden cooldown. It is a season that has started on schedule, delivered a few passing storms, and left the Valley waiting to see which arrives first over the next few days: another burst of monsoon weather or another stretch of punishing heat.
