A surge of Arctic air, reinforced lake-effect snowfall, and an atmospheric river are forecast to affect large portions of the United States from December 31, 2025, into January 2, 2026. Heavy snow is expected downwind of the Great Lakes and across parts of the Northeast, while southern California faces a flash flood risk as an atmospheric river moves onshore around New Year’s Day.
A long-duration solar flare measuring M7.1 at its peak erupted from Active Region 4324 at 13:51 UTC on December 31, 2025. The event started at 13:12 and ended at 14:11 UTC.
Heavy rain and snow are forecast across California and Sierra Nevada through January 4, 2026. The first wave will target southern California with subtropical moisture, followed by a stronger system forecast to bring heavy rain and snowfall across central and northern regions of the state.
Evacuation warnings were issued for Los Angeles County, California for multiple burn scars across the region as an atmospheric river brings in the threat of flash floods and debris flows through New Year’s Day.
A surge of subtropical moisture is forecast to bring moderate to heavy rain to southern and central California on Wednesday, December 31, 2025, with rain spreading north on Thursday, January 1, 2026. A stronger system with a re-intensified atmospheric river is expected to make landfall early Friday, January 2, bringing heavier precipitation along the northern and central California coast.
Severe Tropical Cyclone Hayley is forecast to make landfall over the northern Dampier Peninsula, Western Australia, late on Tuesday, December 30, 2025, as a Category 3 system. The cyclone is expected to bring destructive winds, heavy rainfall, and flash flooding across parts of the west Kimberley coast.
A powerful winter storm named Johannes swept across the Nordic countries over the weekend, killing three people in Sweden and leaving hundreds of thousands without electricity across Sweden, Norway, and Finland. Sweden’s Meteorological and Hydrological Institute (SMHI) issued widespread alerts for strong winds as the system moved north. The storm, known as Hannes in Finland, also caused major travel disruptions, grounding flights and halting rail and ferry traffic.
Winter Storm Ezra is forecast to bring severe winter weather across large parts of the United States from Sunday through Tuesday, December 28–30, 2025, as it moves from the Great Lakes into southern Canada. Heavy snow, blizzard conditions, and hazardous icing are forecast across the Upper Midwest, Great Lakes, and interior Northeast. Snowfall totals of over 30 cm (1 foot) are expected in parts of Michigan’s Upper Peninsula, while ice accumulations of up to 13 mm (0.5 inches) are forecast across interior New England through Tuesday.
A powerful winter storm swept through the U.S. Northeast on December 26–27, 2025, triggering states of emergency in New Jersey and New York, dropping nearly 30 cm (12 inches) of snow and leaving over 120 000 customers without power.
Etna’s eruptive activity intensified rapidly between December 24 and 27, 2025, culminating in short-lived lava fountains about 200 m (650 feet) high and a new lava flow from the upper Voragine crater toward the Valle del Bove. INGV Etna Observatory (OE) raised the Aviation Color Code to Red on December 27 as tremor and infrasound amplitudes reached very high levels.
