Southern California is gearing up for an unusually long heat wave that could persist well into October, according to forecasters. Following a summer that felt particularly sticky and humid for many, this next extended period of heat is set to bring "dangerously hot conditions" across much of the region.
An extreme heat watch for the L.A. County area is slated to begin this Friday and continue through October 8, with the possibility of extensions. The National Weather Service in San Diego has also issued its own extreme heat watch, effective from Friday morning through Wednesday night, for inland and coastal areas of Orange and San Diego counties, in addition to parts of San Bernardino and Riverside counties.
Saturday is expected to mark the peak of this heat wave. Temperatures are forecast to reach triple digits in certain parts of Los Angeles and Ventura counties. Downtown Los Angeles and Pasadena are both projected to hit 100 degrees. Further north, Paso Robles could see 101 degrees, while Ojai is forecast to reach 102 degrees.
This event stands out for its predicted duration. Rose Schoenfeld, a meteorologist with the National Weather Service in Oxnard, who joined the service in 2023, noted it is among the longer-lasting heat waves she has observed in her tenure. Schoenfeld explained that the heat wave, a result of high pressure in Southern California and a noticeable lack of wind, currently lacks a clear end date. Weather service models indicate the high temperatures might persist through the middle of the month.
This unseasonal warmth arrives after Southern California endured a "swampy summer," a period marked by tropical storm remnants and unusually warm ocean temperatures. Those damp conditions contributed to a rise in West Nile virus cases in Los Angeles County, as mosquito populations found prime breeding grounds.
Fortunately, Schoenfeld anticipates this particular heat event will be less humid than the sticky summer conditions. There is, however, a storm not expected to make landfall that could send some moisture toward Southern California over the weekend and into Monday. This might introduce some elevated humidity and a slight chance of thunderstorms and cloud coverage in mountainous areas, though not enough to significantly lower temperatures across the region.
With the heat returning, the National Weather Service advises residents to drink plenty of fluids, stay in air-conditioned rooms, avoid direct sun exposure, and make sure to check on relatives and neighbors. They also issue a stern warning that is always worth repeating: "Car interiors will reach lethal temperatures in a matter of minutes," emphasizing the danger of leaving young children and pets in unattended vehicles.
While this particular heat wave is notable for its length, October heat isn't entirely unusual for the Los Angeles region. As Schoenfeld pointed out, our seasons here can be "a little asynchronous" with more traditional seasonal calendars, with the warm season typically extending from June through October.
