The National Weather Service put the hills of western Sonoma County and the mountains of Sonoma and Napa counties under a heat advisory from 11 a.m. Saturday to 10 p.m. Sunday. Valley towns fall outside it.
Late-day sun over Lake Berryessa in the Napa County mountains on May 22, 2025. The lake sits in the North Bay Interior Mountains forecast zone, one of two North Bay zones under the weekend heat advisory. (Jesse Pluim / Bureau of Land Management)
The National Weather Service put the hills of western Sonoma County and the mountains of Sonoma and Napa counties under a heat advisory from 11 a.m. Saturday to 10 p.m. Sunday. Valley towns fall outside it.