Authorities said nearly 160 were treated for heat-related illnesses during the Los Angeles Rams' first regular-season home game.
Fire Department spokeswoman Margaret Stewart says of those treated, 14 people were taken to the hospital but none were in critical condition.
More than 91,000 people attended the game at Los Angeles Memorial Coliseum as downtown baked in 90-degree weather.
The National Weather Service said a weak onshore flow pushed the mercury across the state where temperatures hit the 80s and 90s in many spots, while temperatures in inland areas hit triple digits.
Downtown San Francisco hit 86 degrees — the second warmest day so far this year.
In Southern California, a red flag warning of extreme fire danger was in effect until noon Monday.