Early Heat Wave Scorches California and Southwest

Record-breaking temperatures expected across the region this week

Mar. 16, 2026 at 7:04pm

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An unusually early and intense heat wave is baking much of California and the Southwest, with temperatures expected to soar well above 90 degrees Fahrenheit and potentially set new all-time monthly records in several cities. The heat dome trapping hot air over the region is being driven by an unusual weather pattern and is expected to last through the weekend, raising concerns about public health risks and the impact on the region's already below-average snowpack.

Why it matters

This early-season heat wave is highly unusual and concerning, as it comes before the typical start of the summer heat season. The prolonged high temperatures could be dangerous for vulnerable populations, exacerbate drought conditions, and increase wildfire risk in the region. The extreme weather is also part of a broader trend of climate change making heat waves more frequent, intense, and long-lasting.

The details

Temperatures are forecast to reach the mid- to high-90s Fahrenheit across much of Southern California this week, with parts of Arizona and Nevada potentially hitting triple digits. Some cities, including San Francisco, Los Angeles, Phoenix, and Las Vegas, may set new all-time monthly heat records. The heat wave is being driven by a persistent high-pressure system, known as a 'heat dome', that is trapping hot air over the region.

  • Temperatures are expected to peak on Thursday, March 21, 2026.
  • The heat wave is forecast to last through the weekend of March 23-24, 2026.

The players

National Weather Service

The federal agency responsible for weather forecasting and issuing weather alerts in the United States.

California

The most populous U.S. state, which is expected to see record-breaking temperatures during the heat wave.

Southwest

The region of the United States encompassing Arizona, Nevada, and parts of California, which is also expected to experience extreme heat.

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What they’re saying

“Daily record-tying/breaking highs will become more common across southern California, the Desert Southwest and into the Great Basin over the next couple of days. These temperatures will serve as a baseline for even more anomalous, more widespread record-breaking heat expected later this week.”

— National Weather Service (nbcnews.com)

“Temperatures will soar to 20+ degrees above normal making it feel more like early June than mid-March.”

— National Weather Service, Las Vegas office (X)

“Moderate to major heat risk is expected. Please check on family and friends without A/C and avoid outdoor recreation during the afternoon hours this week.”

— National Weather Service, San Diego office (X)

What’s next

The National Weather Service will continue to monitor the heat wave and issue updates on record-breaking temperatures and any potential public health risks.

The takeaway

This early-season heat wave is a stark reminder of the impacts of climate change, as global warming makes extreme weather events like this more frequent and intense. The prolonged high temperatures could have serious consequences for public health, the environment, and the region's water resources.