A brown duck swims in a rippling pond beside a spraying fountain.
A duck cools off in a fountain at Panella Park in Stockton. A fall heat wave is descending on the region, driving temperatures into dangerously hot territory in the coming days. (Photo by Zackary Kirk-Newton/Stocktonia)

A fall heat wave is roasting much of California, with a heat advisory in effect for Stockton and much of the Central Valley beginning Saturday morning and running through Wednesday night.

On Friday, the National Weather Service’s Sacramento office extended the heat advisory, which initially was slated to end Monday night. Temperatures as high as 100 degrees are expected in the Sacramento and northern San Joaquin valleys, the Delta and Carquinez Strait, and the foothills, according to the National Oceanic and Atmospheric Administration.

The weather service says temperatures will run 15-20 degrees above average, and there won’t be much cooling overnight. Moderate heat risks are expected in the area, and daily temperature records are expected to be broken.

The heat wave is being driven by a strong ridge of high pressure over the eastern Pacific and the West Coast, according to IQ Air.

NOAA’s Climate Prediction Center, which tracks forecasts and delivers real-time climate monitoring, says the above-average temperatures across California are likely to last through mid-October.

National Weather Service graphic showing moderate heat risk across Northern and Central California, with explanatory heat-safety guidance and a color-coded regional map.
The National Weather Service’s Sacramento office says a moderate heat risk will be a mainstay through the weekend and into next week. (Graphic by National Weather Service)

The prolonged heat could increase the risk of illness for both residents and pets. Officials recommend staying hydrated, limiting outdoor activities between 10 a.m. and 7 p.m. and remaining in cool indoor spaces during the hottest parts of the day.

According to the city of Stockton’s cooling center listing, the Arnold Rue, Stribley, Seifert and Van Buskirk community centers serve as cooling zones, providing air-conditioned spaces for residents seeking relief from high temperatures.

The city says cooling center activation depends on temperatures reaching 100 degrees and sufficient staffing. Residents can check availability and find additional cooling resources through 211 San Joaquin or by dialing 211.