Record-Breaking Heat Wave Sweeps Southern California in March

Southern California is experiencing an unprecedented heat wave in mid-March 2026, shattering temperature records across the region. The unusually warm weather has raised concerns about power grid stability and the risk of heat-related illnesses.

Why is it so hot in March?

According to NBC Los Angeles meteorologist Belen De Leon, a strong, persistent high-pressure system is the primary driver of the heat wave. “During March, we usually see high-pressure systems, but they’re weaker and don’t last very long,” De Leon explained. “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.”

This high-pressure system is exceptionally tall, extending further into the atmosphere than typically observed in March. “The taller and the stronger that high pressure system is, the more air it pushes down,” De Leon said. “And, when air sinks, it warms and it compresses. When that air compresses, it heats up. Plus, we’ve got clear skies, wall-to-wall sunshine — that’s what causes the temperatures to climb so quickly during the day.”

The system’s stationary nature is exacerbating the situation. “It’s not moving; there’s nothing to push it out of the way,” De Leon explained. “That’s why we have this extended heat wave. The heat is building, records are falling, and even our nights are unusually warm.”

Record Temperatures Across Southern California (March 18-20, 2026)

Numerous temperature records were broken on Wednesday, March 18th, and Thursday, March 19th, with more expected on Friday, March 20th. Some notable record-breaking temperatures include:

• 82°F at LAX: Broke the 79°F record from 1988
• 87°F at UCLA: Broke the 84°F record from 1978
• 87°F in Idyllwild: Broke the 75°F record from 2004
• 91°F in Long Beach: Broke the 86°F record from 1960
• 92°F in Palmdale: Broke the 84°F record from 1997
• 93°F in Lancaster: Broke the 85°F record from 2004
• 95°F in Anaheim: Broke the 88°F record from 2010
• 95°F in Santa Ana: Broke the 88°F record from 1978
• 95°F in Downtown Los Angeles: Broke the 87°F record from 1997
• 97°F in Burbank: Broke the 89°F record from 1978
• 98°F in Riverside: Broke the 93°F record from 1914
• 100°F in Woodland Hills: Broke the 92°F record from 1997

The record temperature in Idyllwild also marked the community’s all-time hottest day in March.

Forecast for Thursday and Friday

Belen De Leon indicated that Thursday, March 20th, would also see record-high temperatures. Forecasts from NBCLA’s First Alert Forecast included:

• 97°F in Los Angeles
• 99°F in Van Nuys
• 100°F in West Covina
• 101°F in San Bernardino
• 102°F in Riverside
• 102°F in Lake Elsinore

The Extreme Heat Warning is set to expire at 8 p.m. On Friday, March 21st. “Today and tomorrow, we’re at the top of the roller coaster,” De Leon said. “And then, some relief this weekend.”

Looking Ahead

The high-pressure system is expected to shift eastward this weekend, bringing slightly cooler temperatures to Southern California. However, temperatures will remain above average for this time of year. “So that’s going to preserve our temperatures running way above where they should be for this time of year,” De Leon stated. “Next week, it stays hot and it’s still going to feel like summer.”

Temperatures next week are anticipated to be in the upper 80s and low 90s, though triple-digit temperatures are not expected.