Huge clouds over the city as seen from Treasure Island during heavy rain in San Francisco on April 12, 2026.

The Bay Area saw unexpectedly heavy rain showers on Thursday, with San Francisco receiving close to the monthly average rainfall for May. Roger Gass, a meteorologist at the National Weather Service’s Bay Area office, said downtown San Francisco saw 0.58 inch of rain in the past 24 hours. The monthly May average for rainfall is 0.64 inch. 

The rainfall amount ended up being greater than what had been forecast in the Bay Area, according to Gass.

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The reason for the wet weather was a “cut-off low,” where a low-pressure system is separated from the main airflow.........

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