San Francisco Braces for Record-Breaking March Heat
San Francisco is poised to experience its hottest March day in 152 years of recorded weather data. Temperatures are forecast to soar into the 80s on Tuesday, March 17, 2026, with a potential to reach the 90s, threatening the current March high temperature record of 87 degrees set on March 11, 2005.
Heat Wave Conditions
The anticipated temperature increase of 2 to 5 degrees from Monday is attributed to a strengthening area of high pressure over California. While Tuesday is expected to be the peak of the heat, temperatures will remain largely consistent through Thursday, with a possible additional 2-3 degree rise on Friday. A heat advisory is currently in effect through Friday evening.
Regional Forecasts
San Francisco
Specific areas within San Francisco will experience varying degrees of heat. The Mission District, downtown, North Beach, and Potrero Hill are predicted to reach the upper 80s to low 90s. The inner Richmond and Sunset districts will witness highs in the low to mid-80s. A shallow marine layer may keep the perimeter of the city slightly cooler, in the upper 70s to low 80s. Overnight lows are expected to remain in the 60s, except in Golden Gate Heights, Twin Peaks, Diamond Heights, and Mount Davidson, where temperatures could reach the low to mid-70s.
North Bay
Most of Wine Country is forecast to experience its first 90-degree day of the year, though Petaluma, Napa, and Vallejo may fall just short. Temperatures will be 20 to 30 degrees above normal. Coastal areas will still reach the 80s, with Point Reyes offering the best chance for cooler temperatures. Overnight lows will range from the mid-50s to low 60s in the valleys and mid-60s to mid-70s in the hills.
East Bay
Summer-like heat will grip the East Bay, with bayshore cities warming to the mid-80s to low 90s. Alameda and Point Richmond may experience slightly cooler temperatures in the upper 70s to low 80s due to a shallow marine layer. Overnight lows will be in the low to mid-60s, except above 500 feet in the hills, where they will remain in the upper 60s to mid-70s.
Pacific Coast and Peninsula
A 90-degree day is likely from South San Francisco to Redwood City. Foster City and areas northwest of Highway 101 may remain in the 80s due to a cooler air layer. Pacific beaches will be slightly cooler, in the 70s, but with little breeze, areas less than a mile inland will likely reach the 80s, including Daly City. Overnight temperatures will be slow to cool, remaining near 70 degrees at midnight and dropping to the low to mid-60s by sunrise.
South Bay and Santa Cruz
Record-shattering March heat is expected across the South Bay and Santa Cruz regions, with Santa Cruz forecast to reach the mid-80s to low 90s. The Santa Cruz Mountains, San Jose foothills, and Highway 85 corridor may reach the mid-90s. San Jose is expected to surpass 90 degrees, marking a record for the city in March. A weak afternoon and evening breeze will offer little relief, with temperatures remaining in the 70s through the evening. Lows will be in the 60s in the valleys and 70s in the mountains.
Historical Context: The San Francisco Mint
The U.S. Mint in San Francisco, located near Duboce Triangle where the official weather station is situated, has a rich history. Established in 1854 to serve the California gold rush, the Mint has moved locations three times. The current building was completed in 1937. Originally built in 1874, the building now serves as an event venue, but remains a landmark of the city. The Mint even survived the 1906 earthquake with relatively minor damage, becoming a symbol of San Francisco’s resilience.