San Francisco, Calif. – A rare early September cold front is pushing into Northern California this week, bringing the Bay Area its first widespread chance of light rain since summer began.
According to the National Weather Service, showers are most likely Tuesday afternoon into early Wednesday, with the heaviest rain probabilities focused on the North Bay. Santa Rosa and San Rafael could see a 45% chance of measurable rainfall, while Napa and Oakland hold at 40%. San Francisco, San Jose, and Sunnyvale face a lower 25–35% chance.
The system is not expected to bring significant totals, but slick roads could cause slowdowns on U.S. 101, I-80, and I-280 during the Tuesday evening commute. Drivers are advised to allow extra time and use headlights in light rain.
Santa Cruz, Monterey, and Salinas are forecast for lighter showers, mostly under 30%, with the best chances Tuesday morning into midday. Rain probabilities taper quickly by Thursday, with most of the Bay Area drying out under partly sunny skies.
Another update will be issued if rain chances trend higher, but forecasters stress this event will remain on the lighter side.
Five Day Forecast for San Francisco, Calif.:
- Monday: Mostly sunny, highs near 75.
- Tuesday: Increasing clouds, showers possible by afternoon, highs near 70.
- Wednesday: Spotty morning showers, highs in the upper 60s.
- Thursday: Partly cloudy, highs in the low 70s.
- Friday: Mostly sunny, warming to 76.
