Three atmospheric rivers are expected to impact California between December 20 and 25, 2025, producing 250–500 mm (10–20 inches) of rain over the Sierra Nevada and 75–180 mm (3–7 inches) over southern coastal ranges. The strongest system is forecast to peak on December 23–25 with IVT values surpassing 750 kg m⁻¹ s⁻¹ and AR3–AR4 intensity.
A series of impactful atmospheric rivers is forecast to bring heavy precipitation across California from Friday, December 19, 2025, through Wednesday, December 24, with seven-day precipitation totals expected to exceed 380 mm (15 inches) in parts of the Sierra Nevada.
The Center for Western Weather and Water Extremes (CW3E) at UC San Diego forecasts above-normal precipitation for Northern and Central California between late December 2025 and early January 2026. The latest subseasonal outlook, issued on December 16, indicates high confidence in enhanced atmospheric river (AR) activity and persistent Pacific Ridge conditions during the period from December 22 to January 11, 2026.
Two atmospheric rivers are forecast to bring prolonged heavy rain and mountain snow to the Pacific Northwest and northern California through December 20, 2025. The Weather Prediction Center (WPC) forecasts 100–150 mm (4–6 inches) of precipitation across western Washington and 100–200 mm (4–8 inches) across western Oregon, with locally higher totals in the Cascades and coastal ranges.
An earthquake swarm that began near downtown San Ramon, California, in October remained active on December 15, with three earthquakes recorded within a few hours by the U.S. Geological Survey. The swarm is occurring in a structurally complex fault zone near the Calaveras Fault, where stress is released through repeated small ruptures rather than a single larger earthquake.
Record-breaking rainfall in Death Valley, California, has brought the ancient lake to life, according to satellite images issued by NASA on December 12, 2025.
Historic flooding caused by a major atmospheric river earlier this week impacted large parts of western Washington state, prompting evacuations, emergency declarations, and record river levels. As impacts from that event persist, another strong atmospheric river is forecast to reach the Pacific Northwest on Sunday, December 14, 2025, bringing a prolonged period of precipitation to Washington, Oregon, and northern California through mid-week.
Downtown San Francisco reached only 10°C (50°F) on Sunday, November 30, 2025 – the city’s lowest daily maximum for the date in records dating back to 1874. The unseasonably cold conditions developed under a persistent marine layer and stagnant air pattern, keeping the city unusually cold for late autumn.
Search operations will continue on Monday, November 24, 2025, for a man swept into the Pacific Ocean at Garrapata State Park on Saturday, November 22. A U.S. Coast Guard helicopter briefly sighted what appeared to be a body on Saturday, but visual contact was lost in rough seas and high surf.
Santa Barbara recorded 169.5 mm (6.67 inches) of rain over a three-day period ending November 17 2025, setting a new rainfall record for the county. The series of atmospheric rivers that brought the record rainfall caused at least 7 fatalities in California due to heavy rain, flooding, and rough seas.
