SAN FRANCISCO – While the majority of the county bakes under a sweltering heat dome, the San Francisco Bay Area is experiencing one of its coldest summers in decades.
Temperatures were five degrees below average for June and are currently about four degrees below average for July.
With an average high temperature just shy of 68 degrees overall this season, this has been San Francisco’s coolest summer since 1965.
The current conditions in the Bay Area are more typical of summer in Anchorage, Alaska, according to the FOX Forecast Center.
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SAN FRANCISCO, CALIFORNIA – JULY 21: Fog rolls over the San Francisco-Oakland Bay Bridge on July 21, 2025 in San Francisco, California.
(Photo by Justin Sullivan/Getty Images) -
SAN FRANCISCO, CALIFORNIA – JULY 21: Fog hangs over the San Francisco skyline on July 21, 2025 in San Francisco, California.
(Photo by Justin Sullivan/Getty Images) -
Fog hovers around the Golden Gate Bridge in San Francisco, California Wednesday, July 16, 2025.
(Photo by Jessica Christian/San Francisco Chronicle via Getty Images) -
Fog covers the downtown skyline of San Francisco, California Wednesday, July 16, 2025.
((Photo by Jessica Christian/San Francisco Chronicle via Getty Images)) -
A person walks along Torpedo Wharf near Crissy Field as fog shrouds the downtown view of San Francisco, California Wednesday, July 16, 2025.
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SAUSALITO, CALIFORNIA – JULY 21: Fog obscures the San Francisco skyline as a fisherman prepares to cast a line on July 21, 2025 in Sausalito, California.
(Photo by Justin Sullivan/Getty Images)
In June, there were only five days that reached 70 degrees or warmer, while July has seen just seven such days.
Over the past 30 years, the average high temperature in San Francisco was 71 degrees.
It’s been so unseasonably cool, beachgoers on Tuesday told FOX 2 San Francisco that they were wearing multiple layers.
“It would be nice if it would warm up just a bit,” one of them told FOX 2.
This graphic shows the main factors driving San Francisco’s cold summer season.
(FOX Weather / FOX Weather)
According to the FOX Forecast Center, an enhanced marine layer is one of the main factors in the unseasonably cold weather.
A marine layer is cool, moist air that forms close to the surface of the ocean and then moves inland. It often brings fog and low clouds to coastal areas, which block sunlight and bring temperatures down.
While a marine layer is generally omnipresent in San Francisco, it is currently being enhanced by cold water just offshore, where water temperatures are currently five degrees below average.
WHY IS SAN FRANCISCO SO FOGGY?
This graphic shows the cooler than average water off the coast of San Francisco, CA.
(FOX Weather / FOX Weather)
The region has also not seen any dominant high pressure systems this summer, like the heat dome that is currently gripping the central and eastern U.S.
High pressure traps warm air near the ground and suppresses cloud formation such as those formed by a marine layer.
This graphic shows the coldest summers on record for San Francisco, CA.
(FOX Weather / FOX Weather)
According to the FOX Forecast Center, temperatures are forecast to remain below average this month and thus this season could break nearly century-old records for the coldest summer in the Bay Area.
