Unseasonably Warm December Weather Grips Bay Area

High-pressure system brings sunny skies, dry conditions, and temperatures nearing 70 degrees across the region.

A strong high-pressure system is driving an unusual December warm spell in the Bay Area, with temperatures expected to reach the high 60s to low 70s this week.
San Francisco recorded over 4 inches of rain in November, but December has started dry, with clear skies and mild conditions forecast through mid-month.
The warm weather is notable for its rarity, with similar patterns of heavy November rain followed by December warmth occurring only twice since 1950.
Air quality concerns have been raised due to the high-pressure system trapping particulate matter, prompting a Spare the Air alert for the region.
The dry trend is expected to persist for several weeks, leaving some areas potentially needing irrigation despite November's significant rainfall.