SoCal’s worst heat wave of the year: What’s the timing, who will be hit hardest?

Skateboarders take a sunset cruise at the beach
Skateboarders take a sunset cruise along Alamitos Beach in Long Beach on a hot summer day.
(Allen J. Schaben / Los Angeles Times)

September is bringing searing heat across Southern California, and forecasters are predicting record-setting temperatures.

From Wednesday through Labor Day weekend, the National Weather Service predicts temperatures could reach as high as 115 degrees in some parts of Southern California. It will be the region’s longest and warmest heat wave of the year, said David Sweet, a meteorologist at the National Weather Service in Oxnard. The conditions are expected to last through Monday, though “we don’t see an end to it right now,” Sweet said.

Here’s what you need to know.

Experts remind Southern California residents to stay hydrated, stay out of the direct sun and shelter in air conditioned buildings, if possible.

Aug. 30, 2022

Timing and Conditions

An excessive heat watch is in effect from 11 a.m. Wednesday to 8 p.m. Monday across much of Southern California, including Los Angeles County, Ventura County and the southern Santa Barbara County coast.


For Riverside, Orange and San Bernardino counties, the warning takes effect at 10 a.m. Tuesday and lasts through 8 p.m. Monday.

Sweet said the valleys, mountains, foothills and deserts will bear the brunt of the heat across L.A. and Ventura counties. From Wednesday through Monday, any one of those days, temperatures could reach as high as 115 degrees.

An excessive heat watch is in place for much of Southern California this week. Keep yourself, your kids and your pets safe during hot temperatures with these tips.

Aug. 29, 2022

The hottest conditions are expected Thursday before cooling off slightly into the weekend, though conditions will still be warm, and spiking again on Sunday.

In L.A. County, temperatures could reach 105 in Woodland Hills on Thursday and surge to 110 on Sunday. Lancaster in the Antelope Valley could reach as high as 108 on Thursday and Sunday. In Santa Clarita, Newhall could reach 106 on Thursday and 108 on Sunday.

Downtown Los Angeles could see a high of 93 on Thursday, 94 on Saturday and up to 100 on Sunday.

In Ventura County, Ojai is likely to reach 105 on Thursday and 107 on Sunday, while Fillmore is forecast to reach 102 on Thursday and 106 on Sunday.


High temperatures at Los Angeles County beaches are expected to hover between the mid-80s and 90 over the next several days.

Swimming in the waters could cause illness, the L.A. County Department of Public Health said.

Aug. 29, 2022

Temperatures in San Bernardino, Orange and Riverside counties will build through Friday, rising again on Sunday and Monday, said Casey Oswant, meteorologist at the National Weather Service in San Diego.

Temperatures between 100 and 106 degrees are expected in Riverside through Friday. By the weekend, it could reach as high as 108.

In the Coachella Valley, highs will stay between 110 and 115 degrees. In the high desert, in areas such as Apple Valley and Lucerne Valley near Victorville, temperatures are likely to be between 105 and 110 degrees.

Conditions on the coast will be most severe Sunday and Monday, with highs between 85 and 90 degrees.

People will not get much relief overnight, with temperatures expected to cool only slightly, Oswant said.


Fire danger

Along with the hot temperatures, the forecast includes very low humidity. Together, that creates an elevated fire danger, said Jon Heggie, a battalion chief with the California Department of Forestry and Fire Protection. Fuel moisture, or the amount of water in potential fuel such as vegetation, is “starting to hit rock bottom” across the state, Heggie said.

He added that in parts of Southern California, the fuel moisture is below historical averages.

The high-pressure system over most of California is expected to bring record-breaking temperatures, part of a “self-perpetuating” system that is becoming more extreme as climate change worsens.

Aug. 31, 2022

“What that tells us is the fuel, the brush, is ready to burn, all it needs is the ignition,” Heggie said. “What we need to do is to eliminate the ignition as best as we can.” Heggie advised the public to be very mindful of outdoor activities.

Fire broke out Wednesday the the Grapevine and eastern San Diego County.