California heatwave will last until mid-October

California is cooking – and there is no real relief in sight.

A brutal heatwave is expected to grip large swathes of the state into next week, with forecasters warning oppressive conditions could persist into October.

The National Weather Service has issued heat advisories extending from Southern California to Central California and the Bay Area starting Friday, with triple-digit temperatures expected in inland communities.

Parts of the San Fernando, Simi, Santa Clarita, San Gabriel, Antelope, Apple, Lucerne, Moreno and Coachella valleys could reach 107 to 111 degrees when factoring in the heat index, according to meteorologist Jason Farhang.

Actual daytime temperatures in these areas could reach 102 to 106 degrees.

Coastal communities and mountainous areas from Ventura to San Diego are expected to see temperatures between 90 and 98 degrees, putting millions of residents in areas that typically escape California’s worst heat under unusual stress.

“Coastal areas and mountains are extremely hot with a temperature range of 90°F to 98°F. This subjects many more people to greater heat stress than normal in large populations from Ventura to San Diego counties,” Farhang wrote.

Heat is also expected to bake parts of the East Bay and San Francisco Bay coastline, the western hills of Sonoma County, the Santa Cruz Mountains, Monterey County, the inland North Bay Mountains and parts of the southern Salinas Valley.

Some of these areas could exceed 100 degrees, with little relief after sunset.

“A long-lasting heat wave is expected Friday through early next week in California. Minimum temperatures in the low to mid 70s will provide little or no relief overnight for those without adequate cooling or hydration,” the National Weather Service said.

“Extreme heat warnings are in effect for parts of Southern California and heat advisories are in effect for much of Central California.”

“This is one of the longest-lasting phenomena I’ve seen since I’ve been in this office,” NWS meteorologist Rose Schoenfeld told the Los Angeles Times. Schoenfeld, who has worked in the Oxnard office since 2023, said the heat could last until the middle of the month.

This unusual extent is partly linked to a strong El Niño and above-normal sea surface temperatures.

Officials are urging Californians to take the heat seriously, especially those without reliable air conditioning or access to water.

“Drink water and, if possible, bring water to those who are vulnerable. Take extra precautions when outdoors. Wear light, loose-fitting clothing.”

“Try to limit strenuous activities early in the morning or evening. Take action when you experience symptoms of heat exhaustion and/or heat stroke,” the warning adds.

Residents should also check on elderly relatives and neighbors during the prolonged heat.

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