National Weather Service Heat Advisory Extended Through Thursday Evening Across Southwest California
A Heat Advisory for portions of southwest California will now run through 8 PM PDT Thursday, August 20, 2026.
4 reports on this incident · first at Aug 16, 2026, 3:29 p.m. ET
Hazard products are revised and cancelled as conditions change. Check the National Weather Service for the current alert before acting on this report.
Earlier reports
Aug 16, 2026, 3:45 p.m. ET
National Weather Service Issues Heat Advisory Across Southwest California
According to official records from the National Weather Service Los Angeles, a Heat Advisory is in effect starting at 10 AM Tuesday, August 18, 2026, and expiring at 8 PM PDT Thursday, August 20, 2026. The advisory covers a portion of southwest California across 15 zones, including Cuyama Valley, Santa Clarita Valley, Southern Salinas Valley, San Luis Obispo County Interior Valleys, San Luis Obispo County Mountains, Santa Ynez Mountains Western Range, Santa Barbara County Interior Mountains, Calabasas and Agoura Hills, Western San Fernando Valley, Eastern San Fernando Valley, Santa Susana Mountains, Southern Ventura County Mountains, Western San Gabriel Mountains and Highway 14 Corridor, Eastern San Gabriel Mountains, and Los Angeles County San Gabriel Valley.
Official weather records report high temperatures of 92 to 105 expected, with most areas experiencing peak heat on Wednesday and Thursday. Low temperatures are expected to range from the upper 60s to lower 70s at lower elevations, and mid 70s to lower 80s in the foothills and mountains. Cities listed in the record include Matilija, Newhall, San Marcos Pass, Warm Springs, Rose Valley, New Cuyama, East Los Angeles, Wrightwood, Caliente Range, Chatsworth, Van Nuys, Acton, San Miguel, Topatopa Mountains, Mount Baldy, Malibu Lake, Glendale, Big Pine Mountain, La Canada Flintridge, San Rafael Mountain, Oat Mountain, Creston, Carrizo Plain, Universal City, and Pomona.
Official records state that hot temperatures may cause heat illnesses, with warmer than normal low temperatures adding to heat discomfort. Precautions from the issuing office advise drinking plenty of fluids, staying in an air-conditioned room, staying out of the sun, and checking up on relatives and neighbors. The agency also advises taking extra precautions when outside, wearing lightweight and loose fitting clothing, limiting strenuous activities to early morning or evening, and taking action when seeing symptoms of heat exhaustion and heat stroke.
Aug 16, 2026, 3:41 p.m. ET
Heat Advisory Covers 15 Zones From Cuyama Valley to the San Gabriel Valley
Hot temperatures may cause heat illnesses, and warmer than normal low temperatures will add to the heat discomfort across a portion of southwest California, according to the Heat Advisory record issued by the National Weather Service Los Angeles and published in the agency's raw text product feed.
The advisory takes effect at 10 AM Tuesday, August 18, 2026, and expires at 8 PM PDT Thursday, August 20, 2026. High temperatures of 92 to 105 are expected, with most areas seeing peak heat on Wednesday and Thursday. Low temperatures are expected to range from the upper 60s to lower 70s at lower elevations to the mid 70s to lower 80s in the foothills and mountains.
Where it applies. The record lists 15 zones: Cuyama Valley, Santa Clarita Valley, Southern Salinas Valley, San Luis Obispo County Interior Valleys, San Luis Obispo County Mountains, Santa Ynez Mountains Western Range, Santa Barbara County Interior Mountains, Calabasas and Agoura Hills, Western San Fernando Valley, Eastern San Fernando Valley, Santa Susana Mountains, Southern Ventura County Mountains, Western San Gabriel Mountains and Highway 14 Corridor, Eastern San Gabriel Mountains, and the Los Angeles County San Gabriel Valley.
Communities and locations named in the same record include Matilija, Newhall, San Marcos Pass, Warm Springs, Rose Valley, New Cuyama, East Los Angeles, Wrightwood, Caliente Range, Chatsworth, Van Nuys, Acton, San Miguel, Topatopa Mountains, Mount Baldy, Malibu Lake, Glendale, Big Pine Mountain, La Canada Flintridge, San Rafael Mountain, Oat Mountain, Creston, Carrizo Plain, Universal City and Pomona.
What to do. The Weather Service advises people to drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. Take extra precautions when outside. Wear lightweight and loose fitting clothing. Try to limit strenuous activities to early morning or evening. Take action when you see symptoms of heat exhaustion and heat stroke.
Aug 16, 2026, 3:29 p.m. ETFirst report
NWS Issues Heat Advisory Across Southwest California Through Thursday
In a developing situation, official records from the National Weather Service Los Angeles show a Heat Advisory is in effect for a portion of southwest California. The warning window starts at 10 AM on Tuesday, August 18, 2026, and expires at 8 PM PDT on Thursday, August 20, 2026.
According to National Weather Service records, high temperatures of 92 to 105 degrees are expected across the region, with most areas seeing peak heat on Wednesday and Thursday. Low temperatures are expected to range from the upper 60s to lower 70s at lower elevations and mid 70s to lower 80s in the foothills and mountains. Official records note that hot temperatures may cause heat illnesses and that warmer than normal low temperatures will add to heat discomfort.
The advisory spans 15 zones, including the Cuyama Valley, Santa Clarita Valley, Southern Salinas Valley, San Luis Obispo County Interior Valleys, San Luis Obispo County Mountains, Santa Ynez Mountains Western Range, Santa Barbara County Interior Mountains, Calabasas and Agoura Hills, Western San Fernando Valley, Eastern San Fernando Valley, Santa Susana Mountains, Southern Ventura County Mountains, Western San Gabriel Mountains and Highway 14 Corridor, Eastern San Gabriel Mountains, and Los Angeles County San Gabriel Valley. Cities within the area include Matilija, Newhall, San Marcos Pass, Warm Springs, Rose Valley, New Cuyama, East Los Angeles, Wrightwood, Caliente Range, Chatsworth, Van Nuys, Acton, San Miguel, Topatopa Mountains, Mount Baldy, Malibu Lake, Glendale, Big Pine Mountain, La Canada Flintridge, San Rafael Mountain, Oat Mountain, Creston, Carrizo Plain, Universal City, and Pomona.
National Weather Service records recommend drinking plenty of fluids, staying in an air-conditioned room, staying out of the sun, and checking up on relatives and neighbors. Additional precautions include taking extra precautions when outside, wearing lightweight and loose fitting clothing, limiting strenuous activities to early morning or evening, and taking action when seeing symptoms of heat exhaustion and heat stroke.
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Revision history
- Version 116 Aug 2026, 19:50current
First published.
- Version 116 Aug 2026, 19:41current
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- Version 116 Aug 2026, 19:29current
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- Version 116 Aug 2026, 19:45current
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