An early heat wave baking the West this week obliterated numerous records in California and Arizona on Wednesday and Thursday.
The community of Martinez Lake in Arizona’s Yuma County hit a jaw-dropping 110 degrees Fahrenheit on Thursday, setting a record for the highest March temperature in U.S. recorded history, according to the National Weather Service.
The summerlike conditions are expected to persist and spread east in the coming days.
Across Southern California and the desert Southwest, around 38 million people were under heat alerts. High temperatures in the upper 90s and triple digits have been common throughout the region due to a sprawling heat dome that remains parked over the West.
On Thursday, Palm Springs, California, hit 107, setting a new record for the month of March. The previous record, of 105, was set Wednesday.
The city of Indio in the Coachella Valley also set a record for March on Thursday, when temperatures climbed to 108.
San Francisco hit 85 Thursday, the city’s new hottest March temperature. This week also marked the first time San Francisco has recorded four consecutive days at or above 84 in the winter. The city typically averages only seven days per year at or above that mark, according to weather records.
A number of daily records were broken across California, as well, including a 101 degree reading in Riverside on Thursday. Records set the prior day included highs of 95 in Anaheim, 88 in Sacramento and 85 in San Diego, according to the weather service.
In Arizona, meanwhile, Phoenix recorded its earliest triple-digit day Wednesday, with a high of 102. Temperatures then reached 105 Thursday.
“This is not only the first 100° day of 2026, but it is also the earliest occurrence of 100° in Phoenix (which last occurred on March 26, 1988),” the local office of the weather service wrote Wednesday on X.
Phoenix is forecast to hit 106 Friday and Saturday. An extreme heat warning is in effect for the region through Sunday.
Las Vegas has similarly sizzled. On Thursday, the city set a new March record of 95, according to the local office of the weather service. Temperatures there could reach 100 Friday.
New records were also set in Utah and Colorado: Salt Lake City on Thursday hit 81, the city’s earliest 80-degree day on record and a new record for March. Average highs in Salt Lake City at this time of year normally hover around 57, according to weather records. In Denver, meanwhile, temperatures reached 85 Thursday, another monthly record.
Friday forecasts for Colorado show highs of 84 in Denver, 86 in Fort Collins and 83 in Boulder. On Saturday, the projected highs tick up even further. The weather service warned that extreme heat, combined with gusty winds and low humidity, are increasing the risks of wildfires in the state.
Even parts of Oregon, Idaho and Wyoming are experiencing unseasonably warm conditions. The weather service office in Boise said Wednesday afternoon that the city measured a high of 80.
“This is the earliest date for 80 degrees in records dating back to 1875, and only the second time Boise has ever reached 80 in winter, the other time being March 19, 1997,” the weather service office said on X.
Heat will continue to build heading into the weekend and is expected to move east into the Rockies and the central and southern Plains.
“By Saturday, expect maximum temperatures in the middle to upper 90s across Texas and low to middle 90s as far north as Nebraska and South Dakota,” the agency said Thursday.
This week’s heat dome is caused by a stubborn ridge of high pressure that has trapped hot air over the West like a lid on a pot.
While it can be challenging to tease out the exact influence of climate change on specific weather events, global warming is known to make heat waves more frequent, more intense and longer-lasting.
