The Contra Costa County Fire Protection District is asking cities to close hiking trails and open spaces during the heat wave for health and safety reasons.
A Spare the Air alert has been issued for Saturday due to triple-digit temperatures that are expected to combine with vehicle exhaust to create unhealthy levels.
The National Weather Service extended its excessive heat watch another day, so it will be in effect from 11 a.m. Saturday to 8 p.m. Tuesday. And it now covers.