Extreme Heat Warnings now cover a huge swath of the Southwest, from Death Valley to the Arizona-Mexico border.
Highs will hit 110 to 120 degrees in the hardest-hit desert basins. The warnings run from Thursday through Sunday, and in some spots into Monday.
Mojave Desert and Las Vegas Valley: Highs Up to 120 Degrees
The NWS Las Vegas office has an Extreme Heat Warning in effect from 10 AM Thursday to 8 PM Sunday.
It covers a massive stretch of northwest Arizona, southeast California and southern Nevada. That includes Las Vegas, Henderson, Pahrump, Laughlin, Bullhead City, Kingman and Death Valley National Park.
Highs are forecast at 110 to 120 degrees across the Mojave Desert. The southern Great Basin and Arizona Strip will see 100 to 110.
Overnight lows won’t offer much relief. The Mojave Desert could stay at 80 to 95 degrees even after dark.
Forecasters call it a major to extreme heat risk.
Grand Canyon: Hikers Warned to Stay Off the Trails Midday
The NWS Flagstaff office issued a warning for the lower Grand Canyon, below 4,000 feet, from Thursday through Sunday.
Havasupai Gardens could reach 104 to 109 degrees. Phantom Ranch, deeper in the canyon, could hit 112 to 117.
Day hikers on Bright Angel Trail should go no farther than a mile and a half from the trailhead. Between 10 AM and 4 PM, hikers should be out of the canyon entirely, or resting at Havasupai Gardens or Bright Angel campground.
The NWS says this warning is reserved for only the hottest days of the year.
A second warning covers northern Gila and Yavapai counties below 4,000 feet, including the Verde Valley around Cottonwood, Camp Verde and Payson. That one runs Friday through Sunday, with highs of 108 to 115.
Coachella Valley, Yuma and Southwest Arizona: 120 Degrees Possible
The NWS San Diego office placed the Coachella Valley, San Diego County deserts and San Gorgonio Pass under warning through Sunday. Highs there could reach 115 to 120 degrees.
Palm Springs, Indio, La Quinta and Borrego Springs are all included.
The Inland Empire — Riverside, San Bernardino, Fontana and Ontario — faces highs up to 110 through Sunday. The Apple and Lucerne Valleys, including Victorville and Hesperia, are looking at 104 to 114.
Across the state line, the NWS Phoenix office extended warnings across Yuma, Parker, Blythe and the Imperial Valley. Afternoon temperatures there could reach 110 to 120 degrees through Sunday evening.
Rural areas around Joshua Tree National Park, the Salton Sea and Kofa are forecast at 107 to 120. Closer to Phoenix, Scottsdale, Casa Grande, Gila Bend and Apache Junction face 109 to 118. Maricopa County residents without air conditioning can call 211 to find a cooling center.
Farther west near Ridgecrest and Edwards Air Force Base, the NWS Hanford office warned of long-duration extreme heat with no overnight relief, running from Thursday all the way through Monday night.
Los Angeles, Ventura and Santa Barbara: Heat Arrives This Weekend
The NWS Los Angeles/Oxnard office issued a broad Extreme Heat Warning starting Friday and running through Sunday night.
It covers coastal valleys and inland areas across three counties. Downtown Los Angeles, Burbank, Pasadena, Santa Clarita, Thousand Oaks and Ojai are all included.
Temperatures are forecast at 95 to 110 degrees. Forecasters say the heat could stretch into the following week for some areas.
The Antelope Valley, including Lancaster and Palmdale, faces a separate warning with highs of 105 to 115 from Thursday through Sunday.
The Interstate 5 corridor near Tejon Pass and Gorman gets a Heat Advisory first, Thursday into Friday, then upgrades to an Extreme Heat Warning through the weekend.
What to Do During Extreme Heat
Drink plenty of fluids. Stay in an air-conditioned space when you can.
Never leave children or pets in a parked car, even for a few minutes. Interior temperatures can turn deadly fast.
If you work outside, take frequent breaks in the shade or air conditioning. Try to schedule strenuous activity for early morning or evening instead.
Know the warning signs of heat exhaustion and heat stroke. Heat stroke is a medical emergency — call 911 right away.
Check on relatives and neighbors, especially older adults living alone. If you don’t have air conditioning, look for a local cooling center before the heat peaks.
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