Wednesday, Thursday and Friday are expected to be the hottest days, with highs at least 10 to 20 degrees above normal, but some of the heat should subside by the weekend.
Temperatures are expected to reach 100 to 110 degrees across much of the Interior West, with the most extreme highs reaching 110 and even 120 degrees in the desert. Record-breaking temperatures are predicted in dozens of locations.
Extreme heat watches, warnings and advisories are already in effect for much of inland California, including Las Vegas, Sacramento and Phoenix, as well as southern Arizona, Nevada and southern Utah.
These heat warnings affect around 25 million residents, a number that is expected to increase as the heat approaches its peak later this week.
The desert southwest will experience the most severe heat. The warning, which goes into effect Wednesday, covers Phoenix, Las Vegas, California’s Death Valley and surrounding desert areas.
Heat warnings have also been issued for California’s Central Valley, including areas of Bakersfield, Fresno and Sacramento, and extend as far north as Shasta County and Redding.
Heat warnings also affect areas closer to the coast, including the eastern San Francisco Bay area, and may be expanded.
The Met Office’s new Heat Risk product, which highlights areas most susceptible to temperatures that could pose a threat to human health, predicts relatively mild conditions are expected Monday and Tuesday before quickly turning to “severe,” or Level 3 of 4, impacts on Wednesday for much of the Southwest and California’s Central Valley, and remaining at that level through Friday.
Level 4, or “extreme,” heatstroke risk conditions are expected in several locations across the desert in southeastern California and southern Nevada on Thursday and Friday.
Where recording may occur
The chances of record heat will be scattered on Monday but will become more widespread by Thursday.
Temperatures in Las Vegas are expected to reach 108 degrees on Wednesday, one degree warmer than the record of 109 degrees set on June 5. Highs are expected to reach 111 and 110 degrees on Thursday and Friday, which would set new calendar-day records.
Overnight low temperatures are also at risk of breaking records in Las Vegas, dipping only into the mid-80s Fahrenheit later this week.
In the desert Southwest, temperatures will easily top 110 degrees Fahrenheit in the hottest places. Phoenix is expected to hit a record 112 degrees on Thursday, while Needles in eastern California, near the Arizona border, is expected to hit 114 degrees.
Death Valley, California, notorious for being one of the hottest places on Earth, is set to see several days of temperatures exceeding 120 degrees. Highs are expected to reach 122, 124, 123 and 120 degrees from Wednesday through Saturday. If Death Valley reaches 124 degrees during this time, it will be the hottest it has been this early in the season.
To the north, many parts of California’s Central Valley are expected to exceed 105 degrees, potentially breaking records by Wednesday.
The record heat will reach Northern California by Thursday and briefly reach the Pacific Northwest on Friday.
Why is this heat so dangerous?
The Meteorological Agency said the high temperatures in the afternoons were the most notable, but the prolonged heatwave, which will not allow temperatures to fall overnight, is particularly dangerous.
Heat waves early in the year are also a particular concern as people are still not used to the hot weather.
For people without access to proper shelter or air conditioning, such heat can be deadly: A heatwave that hit the southern US in 2023 led to a record number of heatstroke deaths, according to the Associated Press.
Last July, Phoenix saw its hottest month on record for a U.S. city, with average temperatures exceeding 100 degrees Fahrenheit, and at least 645 heatstroke deaths were recorded last summer.
The heat may ease a bit this weekend, but above-normal temperatures are likely to persist in the West until at least mid-June.
This heatwave coincides with the hottest period in Earth’s history, with each of the past 12 months also seeing record temperatures.
Last week alone, India experienced record heatwaves that left many dead, while temperatures in Iraq topped 50 degrees for the first time this year.
In the United States, South Florida and South Texas repeatedly recorded record heat in May. In Punta Gorda, Florida, the temperature reached 101°F on May 30, the hottest temperature recorded in Southwest Florida so far this year.
The increased heat in the West is probably just a sign of even more severe conditions to come by midsummer, as human-induced climate change makes high temperatures more extreme, widespread and long-lasting.
