https://www.mercurynews.com/2021/07/08/bay-area-weekend-heat-wave-cooling-centers-in-east-bay/

An isolated Bay Area heat wave that will lift the thermometer to triple digits in the farthest inland areas of Contra Costa and Alameda counties will keep some cooling centers open this weekend.

Officials in Contra Costa and Alameda counties made clear that despite the state’s reopening and relaxed mask rules that began June 15, masks are required for all visitors inside the cooling centers, regardless of vaccination status.