A prolonged and dangerous heat wave settled over Southern California on Wednesday, prompting the National Weather Service to issue an Extreme Heat Warning for the Antelope Valley and a Heat Advisory for much of Los Angeles County, including the mountains, valleys and beaches, through Monday evening.
The National Weather Service's Los Angeles/Oxnard office said the heat will build through the week, with Thursday through Sunday expected to bring the hottest conditions. Forecasters said "hotter than normal conditions will continue through at least early next week," warning of elevated risks for heat-related illness as both daytime highs and overnight lows run well above seasonal norms.
The Los Angeles County Department of Public Health urged residents to take precautions to avoid heat exhaustion, heat stroke, heat cramps and heat-related death, and encouraged residents to check conditions in their specific neighborhoods using the NWS HeatRisk map.
Temperatures and Forecast
The Antelope Valley was placed under an Extreme Heat Warning — the more severe of the two alert levels — effective 10 a.m. Thursday through 8 p.m. Monday, with highs forecast between 100 and 108 degrees. The National Weather Service said the warmest valley locations could see readings as high as 107 degrees.
A Heat Advisory covers a broader swath of the region from 10 a.m. Thursday through Monday evening, including the Santa Clarita Valley, San Fernando Valley, San Gabriel Valley, Santa Susana Mountains, the Interstate 5 corridor and both the western and eastern San Gabriel Mountains, with highs of 97 to 107 degrees.
Downtown Los Angeles and the inland coast are expected to see highs of 88 to 96 degrees. The Los Angeles County beaches, Malibu Coast and Palos Verdes Hills — including Santa Monica — are under a separate coastal Heat Advisory in effect from 10 a.m. Thursday to 8 p.m. Monday, with highs generally between 80 and 86 degrees. Forecasters said warm overnight conditions would bring less relief than usual, even along the coast.
Inland desert areas will see the most extreme readings, with Palm Springs forecast to reach about 111 degrees. Thursday is expected to be the hottest day across the region, with only limited, possibly minimal cooling by Friday.
The National Weather Service attributed the heat to a strong ridge of high pressure — a heat dome — combined with weakening onshore, or marine, flow. Moisture from monsoonal weather patterns and distant tropical systems in the eastern Pacific was expected to raise humidity levels and keep overnight temperatures elevated, limiting the body's ability to cool through sweating.
Forecasters also warned of an increased wildfire risk, particularly along the Interstate 5 corridor and Grapevine, along with dangerous surf and rip currents driven by swells from distant tropical storms. A Beach Hazards Statement is in effect for Ventura County, Malibu Coast and Los Angeles County beaches through Sunday evening, with breaking waves of 3 to 6 feet and an increased risk of ocean drowning.
Safety Precautions
Public health officials urged residents to stay hydrated throughout the day, even when not feeling thirsty, and to avoid outdoor activity during the hottest hours. Those who must go outside should wear lightweight, light-colored clothing, a hat and sunscreen of SPF 15 or higher.
Officials also warned residents never to leave children or pets in a vehicle, even briefly, noting that cars can heat up quickly even with windows partly open, and urged anyone who sees a child or pet alone in a vehicle to call 911.
Residents were asked to check on those most vulnerable to heat, including people who are sick or have chronic conditions, older adults, pregnant women, children, people who live alone, pets, and outdoor workers and athletes.
"Heat causes more deaths in the U.S. annually than floods, storms, and lightning combined. Those most likely to get ill during the heat include older adults, young children, outdoor workers, athletes, and individuals with chronic medical conditions," said Dr. Muntu Davis, Los Angeles County health officer. "If you or someone around you experiences symptoms of heat stroke or heat exhaustion, such as dizziness, nausea, rapid heartbeat, confusion, or passing out, seek medical help immediately."
Officials said residents should call 911 immediately if they or someone else shows signs of confusion, fainting, hot or red skin, a body temperature of 103 degrees or higher, a fast or strong pulse, headache, dizziness or nausea.
Those without air conditioning were encouraged to take cool showers, limit stove and oven use, and visit a library, cooling center or shopping mall. County and city officials have opened cooling centers, splash pads and community pools for residents without access to air conditioning; locations can be found at ready.lacounty.gov/heat or by calling 211, which operates 24 hours a day.
How This Heat Wave Compares
While dangerous, particularly inland, the current event is not unprecedented for the region. The National Weather Service said forecast highs are running roughly 4 to 8 degrees above seasonal averages. The 1991-2020 climate normal high for downtown Los Angeles in late July is about 82 degrees. In a typical July, downtown Los Angeles reaches 90 degrees on only about three days and hits 100 degrees roughly once every five years, meaning a stretch of low-to-mid-90s highs downtown is notable but not extraordinary. Downtown Los Angeles' all-time record high is 113 degrees, set Sept. 27, 2010, while the July monthly record stands at 107 degrees.
Inland valleys and deserts routinely see triple-digit heat in late July, making the 100- to 108-degree range forecast for the Antelope Valley characteristic of the season, even as it poses serious health risks. Along the coast, the marine layer is expected to keep Santa Monica and other beach communities in the upper 70s to mid-80s, well below inland highs.
This heat wave arrives amid a record-warm year globally. The National Oceanic and Atmospheric Administration reported that the January-through-June global surface temperature departure was the third-highest in the 177-year record, behind only the same periods in 2024 and 2025, and has said it is "virtually certain" 2026 will rank among the 10 warmest years on record.
Southern California's event is milder than several other major heat waves that have struck the globe this year. Western Europe recorded its hottest June on record, with Germany setting a new national high of 41.5 degrees Celsius, or 106.7 degrees Fahrenheit, on June 27, surpassing a record set just a day earlier. Deadly wildfires followed across Spain, Portugal, France, Greece, Italy and Turkey, killing at least 15 people by mid-July.
South Asia endured a severe heat wave in April and May, with temperatures in India, Pakistan and Bangladesh approaching or exceeding 45 to 50 degrees Celsius, or 113 to 122 degrees Fahrenheit. A rapid study by World Weather Attribution linked the event to at least 37 heat-related deaths in India and 10 in Karachi, Pakistan.
In the United States, a heat dome over the eastern part of the country around the Fourth of July set at least 148 daily high-temperature records and was linked to at least 44 deaths, including 29 in New Jersey. A second heat dome later moved west, pushing Phoenix to 113 degrees and setting an all-time record of 109 degrees in Salt Lake City on July 12.