California braces for record heat in March as temperatures top 100 degrees
Warmer, drier conditions intensify across the region this week, with an early March heatwave potentially bringing record temperatures of 100 degrees to Southern California.
A record-setting “scorching” heat wave is underway in Southern California on March 17, forecasters said, with dangerous heat reaching up to triple digits expected to spread across much of the Southwest.
The heat is expected to continue into the weekend, according to the National Weather Service, and several daily records and even records for the entire month of March could be challenged or broken.
On the morning of March 17, heatwave warnings were issued for more than 18 million people in Southern California, southern Nevada, and parts of Arizona. Millions more people in the region are under heat advisories. The Los Angeles Weather Bureau warned of “dangerously hot.”
“The risk of heat stroke is high this week, and as warm conditions continue overnight, the risk of heat stroke will further increase,” the Japan Meteorological Bureau said.
Forecasters say what makes this heatwave so unusual and dangerous is not just the heat level, but also the timing. Temperatures are expected to reach the low 90s and triple digits in some major cities, weeks or months earlier than normal.
“The effects of this heat will extend beyond daily temperature records, including accelerated snowmelt, drier vegetation, and increased stress on water resources across the West,” said AccuWeather meteorologist Elizabeth Danko.
Here’s what we know about the Southwest heatwave.
How long will the heat wave last?
An “unusually early” heatwave is expected in Southern California on March 17, with highs potentially reaching nearly 100 degrees, according to the National Weather Service.
Los Angeles is under heat warnings and advisories until March 20th. Temperatures this week are expected to be 15 to 30 degrees above average for this time of year, local forecasters said, with daily and even monthly records likely to be set in many areas. The heat in Los Angeles is expected to peak between March 17 and March 19, with highs in the coastal plains, valleys and inland areas expected to reach between 90 degrees and 103 degrees. Coastal areas can get hot in the 80s to 90s.
Forecasters in Los Angeles say next week will be a little cooler, but temperatures will still be 10 to 15 degrees above normal.
Temperatures are expected to exceed 100 degrees in much of the desert southwest by the afternoon of March 18, the weather bureau said.
The heat dome will spread to multiple states and affect as many as 70 million people over the weekend and possibly early next week, according to AccuWeather.
These major cities could break heat records
Some parts of the southwestern states could break daily heat records and even March records. According to AccuWeather, record high temperatures are possible from California to the Rocky Mountains, including cities such as Salt Lake City, Albuquerque and Denver.
The Bureau of Meteorology said, “If temperatures are this high early this year, the record high temperature could be broken by as much as 10 degrees.”
Los Angeles could break the March record high of 99 degrees, and if the heat wave lasts five days, it would be the longest ever recorded in the region (the current record is a four-day heat wave in March 2015), AccuWeather reported. Downtown Los Angeles could break daily heat records, according to the National Weather Service.
- March 17th: 1914, 94 years old
- March 18th: 1997, 87 years old
- March 19th: 1997, 97 years old
- March 20th: 1997, 93 years old
According to AccuWeather, Phoenix could reach up to 106 degrees from March 19 to March 21, about 20 to 30 degrees above historical average temperatures. The earliest recorded temperature in Phoenix to reach 100 degrees was March 26, 1988, but on average Phoenix does not reach 100 degrees until May.
According to the National Weather Service, the records in question in Phoenix are:
- March 17th: 99 degrees
- March 18th: 95 degrees
- March 19th: 96 degrees
- March 20th: 97 degrees
Las Vegas could also reach 100 degrees this week, weeks earlier than the usual triple-digit season. If temperatures exceed 93 degrees, Las Vegas will break its March record, which was last set in 2022.
California’s Coachella Valley, which includes Palm Springs, could reach highs of 105 or 110 degrees this week, according to the National Weather Service.
Record-breaking heat continues in Northern California. On March 16, Redwood City broke its March temperature record, according to the San Francisco Weather Bureau. High temperatures in San Francisco could reach the low 80s, breaking daily records that have stood for decades, according to AccuWeather.
Heat wave could bring early fire season
Southern California’s heatwave comes after average temperatures in the region were up to 8 degrees above normal in December and January 2025.
The combination of recent Santa Ana winds and heat will accelerate the process of drying out green vegetation, known as “hardening,” which usually doesn’t happen until May or June, said Paul Pastelok, AccuWeather’s chief long-range expert.
This means we could see an increase in wildfires early this year as dry vegetation acts as fuel. Cal Fire Chief Brent Pascua said there is still moisture in the vegetation, but officials are closely monitoring the situation and the current lack of rainfall. Click here for details.
Contributor: Paris Barraza
