December 2026 Winter Pattern: Where the Season Starts
December 2026 planning guide for the start of the 2026–27 winter outlook: southern storm track, northern warmth odds, and forecast uncertainty.
Published 2026-10-17; based on outlooks available October 17, 2026.
Read the national 2026–27 winter outlook for the full regional context.
The first month of the outlook
December is included in both CPC's November–January discussion and NOAA's December–February winter outlook. The stronger El Niño signal supports attention to the southern storm track from California and the Southwest through the Gulf states and East Coast. The maps cannot resolve whether the first active period arrives in early or late December.
The northern United States has elevated odds of above-average seasonal temperature in NOAA's outlook. That is an average over three months. A single intense cold spell, lake-effect snow event, or mountain storm remains possible wherever local conditions line up.
Rain, snow, and the freezing line
Precipitation outlooks count total water, including rain and melted snow. In the Southwest, an active storm sequence may bring valley rain and high-elevation snow. Farther east, storm-track position and surface temperature decide whether an event falls as rain, snow, sleet, or freezing rain.
Do not convert NOAA's wet category into a specific number of snow days. That conversion depends on storm timing, cold air supply, elevation, and the structure of each storm. The same area may get most of its seasonal surplus from a few heavy rain events.
When the forecast becomes actionable
For holiday travel, check the local NWS forecast repeatedly in the week before departure and use probabilistic snow and ice ranges in the final days. Pay special attention to mountain passes, bridges, and areas with poor drainage. Make changes based on event guidance and official warnings, not an October seasonal outlook alone.
The December outlook may be revised before the month begins. Use this article as context for the season's possible pattern and the current CPC update for the latest probabilities.
Sources and live forecast tools
Seasonal outlooks describe probabilities for three-month averages. For immediate safety decisions, follow local National Weather Service forecasts and warnings.