Bay Area Braces for Marathon March Heat Wave

Temperatures forecast to soar 20-30 degrees above normal, shattering records

Mar. 15, 2026 at 7:09pm by Ben Kaplan

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The National Weather Service is forecasting a prolonged and record-breaking heat wave across the Bay Area, with temperatures expected to surge into the 90s from March 17 to 21. This 'marathon' of high temperatures, up to 30 degrees above normal for this time of year, could tie or break numerous March heat records in cities like San Francisco and San Jose.

Why it matters

This extreme and extended heat wave poses serious risks, especially for vulnerable populations like the elderly and those with underlying health conditions. It also highlights the growing threat of climate change, as such record-shattering temperatures would have been nearly impossible in past decades before the effects of greenhouse gas emissions.

The details

The weather service has issued a heat advisory for the entire Bay Area, excluding Solano County, from Monday through Friday. San Francisco is forecast to reach highs of 84 degrees or higher each day, which would tie the city's longest such streak in any month since 2007. Elsewhere, San Jose could hit 95 degrees, breaking its March record by 6 degrees, while some inland areas may even flirt with 100 degrees.

  • The heat wave is expected to last from March 17 to March 21.
  • A heat advisory is in effect from 10 a.m. on Monday, March 17 to 8 p.m. on Friday, March 21.

The players

National Weather Service

The federal agency responsible for weather forecasting and issuing weather-related advisories and warnings.

Karleisa Rogacheski

A meteorologist at the National Weather Service office in Monterey.

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What they’re saying

“It is going to be a marathon.”

— National Weather Service (San Francisco Chronicle)

“Near Oakland you could be cracking 90 … near 100 if you're going to Pinnacles (National Park).”

— Karleisa Rogacheski, Meteorologist (San Francisco Chronicle)

What’s next

The high-pressure system responsible for the heat wave is predicted to finally begin breaking down by Saturday night, allowing for some relief by Sunday.

The takeaway

This extreme and prolonged heat wave underscores the growing threat of climate change, as such record-shattering temperatures would have been nearly impossible in past decades. It serves as a stark reminder of the need to address greenhouse gas emissions and prepare for more frequent and intense heat events in the future.