Phoenix Weather News - September 4, 2025

PHOENIX, AZ - Thursday, September 4, 2025 - Residents across the Valley faced a surge in monsoon activity today as remnant moisture from Hurricane Lorena combined with the seasonal monsoon flow to spark scattered thunderstorms and raise flood concerns.

A Flood Watch went into effect at noon for Maricopa County, remaining in place through this evening as meteorologists warned of storm clusters capable of producing heavy downpours, damaging wind gusts, dangerous cloud-to-ground lightning, and blowing dust that could reduce visibility on area roadways. The National Weather Service cautioned drivers to be prepared for sudden reductions in visibility due to wind-driven dust.

Despite the threat of rain, daytime temperatures remained well above seasonal norms. Phoenix recorded a high of 35 °C (95 °F) today, with humidity levels keeping overnight lows near 28 °C (82 °F). The combination of heat and moisture led to unstable atmospheric conditions, fueling thunderstorm development predominantly during late afternoon and evening hours.

Localized downpours resulted in street flooding in low-lying areas, prompting city crews to respond to water rescues and clear debris from storm drains. Fortunately, no major damage or injuries have been reported as of press time, though motorists were urged to “turn around, don’t drown” when encountering flooded roadways.

As the Valley heads into the weekend, storm chances will persist into Friday, with high temperatures expected to dip slightly into the mid-90s, roughly 10 °F below early-September averages. Residents are advised to monitor local weather updates and heed any additional advisories from the National Weather Service.