Southern California is experiencing an unusual and intense heat wave for mid-March, shattering daily records across the region. Temperatures have soared well into the 90s and even exceeded 100 degrees in some areas, prompting an Extreme Heat Warning through 8 p.m. Friday. The early-season heat is raising concerns about strain on the power grid and potential health risks for vulnerable populations.
The culprit behind this unseasonable warmth is a powerful, persistent high-pressure system dominating the Southwest, according to NBC Los Angeles meteorologist Belen De Leon. This isn’t a typical March high-pressure system; it’s significantly stronger and extending much higher into the atmosphere than is usually seen this time of year. The conditions are creating a “summer-like” feel, despite it being early spring.
A ‘Very Tall’ High-Pressure System
De Leon explained that while high-pressure systems are common in March, they are typically weaker and short-lived. “But right now, we have a massive, record-strong, high-pressure system over the Southwest, and it’s not just affecting us here in Southern California,” she said. The system’s height is a key factor. “The high-pressure system is very tall. So, the taller and the stronger that high pressure system is, the more air it pushes down,” De Leon stated. As air descends, it warms and compresses, leading to rapidly rising temperatures, especially under clear, sunny skies.
What’s particularly concerning is the system’s immobility. “It’s not moving; there’s nothing to push it out of the way,” De Leon noted. “That’s why we have this extended heat wave. The heat is building, records are falling, and even our nights are unusually warm.”
SoCal Heat Records, Smashed
On Wednesday, numerous heat records fell across Southern California, as reported by NBCLA meteorologist David Biggar. More records, including all-time March highs, are anticipated through Thursday, and Friday. Palm Springs is potentially on track to approach the record for the hottest March day in U.S. History, according to Biggar.
Here’s a breakdown of some of the record-breaking temperatures recorded on Wednesday:
- 82 degrees at LAX: Broke the 79-degree record from 1988
- 87 degrees at UCLA: Broke the 84-degree record from 1978
- 87 degrees in Idyllwild: Broke the 75-degree record from 2004
- 91 degrees in Long Beach: Broke the 86-degree record from 1960
- 92 degrees in Palmdale: Broke the 84-degree record from 1997
- 93 degrees in Lancaster: Broke the 85-degree record from 2004
- 95 degrees in Anaheim: Broke the 88-degree record from 2010
- 95 degrees in Santa Ana: Broke the 88-degree record from 1978
- 95 degrees in Downtown Los Angeles: Broke the 87-degree record from 1997
- 97 degrees in Burbank: Broke the 89-degree record from 1978
- 98 degrees in Riverside: Broke the 93-degree record from 1914
- 100 degrees in Woodland Hills: Broke the 92-degree record from 1997
Biggar also noted that Idyllwild’s record temperature broke the community’s all-time hottest day record for March.
As Southern Californians cope with the extreme heat, the increased temperatures are placing a strain on power grids, as reported by Macy Jenkins for NBC4 News on Wednesday, March 18, 2026.
Thursday and Friday: ‘The Top of the Roller Coaster’
De Leon anticipates Thursday will also notice record-high temperatures. NBCLA’s First Alert Forecast predicts the following temperatures:
- 97 degrees in Los Angeles
- 99 degrees in Van Nuys
- 100 degrees in West Covina
- 101 degrees in San Bernardino
- 102 degrees in Riverside
- 102 degrees in Lake Elsinore
The Extreme Heat Warning remains in effect until 8 p.m. Friday. “Today and tomorrow, we’re at the top of the roller coaster,” De Leon said. “And then, some relief this weekend.”
The extended heat wave also increases the risk of heat-related illnesses, as reported by Lauren Coronado for NBC4 News on March 17, 2026.
What’s Next?
Looking ahead, De Leon says the high-pressure system will begin to shift eastward this weekend, bringing slightly cooler temperatures to the region. However, she cautioned that temperatures will still remain well above average for this time of year. “So that’s going to keep our temperatures running way above where they should be for this time of year,” she explained. “Next week, it stays hot and it’s still going to feel like summer.”
Next week’s temperatures are expected to be in the upper 80s and low 90s, though thankfully, triple-digit heat is not currently forecast.
This unusual March heat wave serves as a reminder of the increasing frequency and intensity of extreme weather events. Residents are encouraged to stay hydrated, seek shade, and check on vulnerable neighbors and family members. Updates on the heat wave and any potential changes to the forecast will continue to be provided by NBCLA’s weather team.
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