RELATED: Weather forecast for Monday
Some attended a blues festival in Martinez, while others hit the beaches.
In the North Bay, hot weather and high fire danger forced the closure of Mount Tamalpais State Park.
Mill Valley Fire Department Chief Michael St. John was concerned about a very real fire threat near Mt. Tam. "Particularly in areas above 1,000 feet, if it gets ignited, there's potential for explosive fire growth," John said.
It must be September if you can hit the beach at Crissy Field in San Francisco. "We've been waiting and waiting all summer for a day like this, wonderful," San Francisco resident Patricia Ortiz said.
Weather officials said the high temperatures across a portion of the area pose a moderate risk for people who are sensitive to the heat.
Residents and visitors should take frequent breaks and drink fluids regularly.
Weather officials remind people to avoid leaving a child or pet in a car where temperatures can rise rapidly.
If you like hot weather, Monday is expected to be even warmer.
Bay City News contributed to this report.