The possibility of heat-related illnesses prompted the National Weather Service to issue a weather advisory for Saturday and Sunday in parts of the San Francisco and Monterey bay areas.
Residents and visitors of inland areas where temperatures could rise into the mid-90s are encouraged to take precautions to stay cool, meteorologist Anna Schneider said.
Weather officials identified Concord, Livermore and areas near Fremont and Vacaville as places that pose the most danger on Saturday for people who are sensitive to heat.
The temperature on Saturday could reach 93 degrees in Livermore, 92 degrees in Concord and Fairfield, and 86 degrees in Santa Rosa and San Jose.
Outdoor workers are encouraged to stay hydrated and take breaks in the shade as often as possible. Residents are encouraged to check on their neighbors who are sick, elderly or have no air conditioning.
Drivers are urged to avoid leaving children and pets inside vehicles. Residents and visitors are cautioned to stay hydrated, limit strenuous outdoor activities and find shade when necessary.
A sea breeze should keep coastal locations cool this weekend with temperatures in the 60s and 70s, weather officials said.
Warmer weather away from the coast could continue into Monday.