Hot conditions with afternoon highs in the upper 90s to up to 108 degrees are expected for the Memorial Day holiday.
Impacted areas are forecast to include the Delta region, Northern San Joaquin Valley, and adjacent foothills.
The warning is in effect from noon Monday, May 31 through 9 p.m. PDT Tuesday, June 1.
Hot conditions will arrive for the holiday, with afternoon highs in the upper 90s to around 108 degrees, hottest on Memorial Day. A Delta breeze is expected to provide some cooling Tuesday for the Sacramento and Stockton areas but it will still be hot further inland.
This is a widespread moderate to high heat risk, according to the National Weather Service. Heat-related illnesses such as heat exhaustion and heat stroke can occur due to prolonged exposure to hot temperatures. Most vulnerable include children, the elderly, those without air conditioning, and those with chronic ailments.
Hottest afternoons are forecast to occur on Memorial Day (Monday) and Tuesday. Holiday travelers, hikers, campers, and outdoor enthusiasts should prepare for the excessive heat.
Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. Young children and pets should never be left unattended in vehicles under any circumstances. Take extra precautions if you work or spend time outside. When possible reschedule strenuous activities to early morning or evening. Know the signs and symptoms of heat exhaustion and heat stroke. Wear lightweight and loose fitting clothing when possible.
To reduce risk during outdoor work, the Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air conditioned environments. Anyone overcome by heat should be moved to a cool and shaded location. Heat stroke is an emergency; Call 9-1-1.