Bay Area Records Hottest March Ever as Heat Dome Finally Breaks

The San Francisco Bay Area has just concluded its hottest March on record, marking a period of extreme heat and a stark lack of precipitation across California. A persistent heat dome, which hovered over the region for nearly a month, pushed temperatures to historic levels, leaving meteorologists concerned about the upcoming fire weather season.

A Historic Heat Wave in San Francisco

The intensity of this weather event was most evident at the National Weather Service’s 150-year-old climate site in downtown San Francisco, which recorded its hottest March ever. This trend wasn’t isolated to the city; at least nine different weather stations across the Bay Area recorded new highs for the month. A late-month heat wave further amplified the trend, driving temperatures 3 to 9 degrees above normal.

The Transition to April: A Brief Cooldown

The record-breaking streak is finally ending as a trough of low pressure moves in from the Eastern Pacific near Washington. This system is expected to trigger a gradual cooling trend, with temperatures dropping several degrees between Sunday, and Monday. By Tuesday, a cold front moving through the region will bring temperatures back to seasonal averages.

Expected Rainfall and Regional Impact

While the cooldown is welcome, the accompanying rain will be light. A cold front passing between Tuesday afternoon and Tuesday evening is expected to produce approximately a tenth of an inch of rainfall. The distribution will vary by region:

• North Bay: Coastal mountains may see up to a quarter of an inch.
• South Bay: This region is expected to receive the rain first.
• East Bay: This area may only see a trace, or a few hundredths of an inch.

Steady rain is forecast for Tuesday, followed by off-and-on showers on Wednesday that could include brief, heavy downpours. While the rain is considered beneficial and poses no flooding risk, the National Weather Service warns that roads may be slicker than usual due to oil accumulating on the asphalt during the 30-plus day dry spell.

Looking Ahead: The Return of the Heat

The respite from the heat will be short-lived. Forecasters expect another ridge of high pressure to build by Friday, which will send temperatures soaring back into the mid-to-upper 70s over the weekend. Above-normal temperatures are expected to linger throughout early April, continuing the trend of a warm April forecast.

Key Takeaways

• Record Heat: March 2026 was the hottest on record for the Bay Area, including the NWS’s 150-year-old downtown San Francisco site.
• The Cause: A heat dome remained over the region for nearly a month.
• Immediate Forecast: A cold front arrives Tuesday, bringing light rain (0.1″ to 0.25″) and a temporary return to seasonal temperatures.
• Future Outlook: High pressure returns Friday, bringing temperatures back to the mid-to-upper 70s for the weekend.