An excessive heat warning is in effect through Wednesday night in much of the greater Bay Area because of temperatures that could reach 110 degrees in some inland locations and up to 96 degrees in downtown San Francisco, according to the National Weather Service.
Tuesday saw triple-digit temperatures by the early afternoon in places like Olema Valley in Marin County that had a 104-degree reading and Livermore at 100 degrees as of 1 p.m.
The hot weather will continue Wednesday and will be accompanied by some offshore winds between 20-30 mph that prompted the weather service to issue a red flag warning for inland parts of Monterey County and other nearby regions from 3 a.m. Wednesday to 8 p.m. Thursday.
The Bay Area Air Quality Management District has also issued a Spare the Air alert for Wednesday, the third straight day of the alerts, because of expected unhealthy levels of smog in the region.
Among forecasted high temperatures Wednesday are 108 degrees in Concord, 106 in Livermore, 104 in San Rafael, and 101 in San Jose, according to the weather service, which said daily high temperature records for this date in October are expected to be broken in many places around the Bay Area on Tuesday and Wednesday.
The weather service encourages residents and visitors in the region to never leave people or pets in hot cars, to limit outdoor activities during the afternoon and evening, and to stay hydrated and take cooling breaks.
Forecasters expect there will be gradual cooling later in the week but still temperatures in the high 90s to low 100s in some inland locations through the weekend before widespread cooling is expected early next week.
"Simply put, this is a long duration heat event and people need to remember heat-related illness is cumulative and impacts will remain," the weather service said Tuesday afternoon.
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