NOAA December 2025 Outlook: Here’s How the Early Ski Season is Shaping Up

Yesterday, the NOAA released its monthly outlook for December 2025. Below is a summary for those unfamiliar with meteorological terminology, and the full discussion further down for those who are.

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• Related: Farmers’ Almanac Winter 2025-26 Forecast: Cold and Snowy Winter Ahead. But Where?
• Related: NOAA Winter 2025-26 Forecast: Nor’easters and Pacific Powder—This is Where it Will Snow

TL;DR – December 2025 looks promising for northern and high-elevation resorts, with colder-than-average temperatures and good snow chances across the Pacific Northwest, Northern Rockies, and Great Lakes. Southern and lower-elevation areas, including much of the Southwest and Southeast, are expected to stay warmer and drier. However, short cold spells could briefly improve conditions early in the month.

NOAA December 2025 Temperature Outlook

Western U.S. and the Rockies

• Northern Rockies & Pacific Northwest: Cooler than normal temperatures are favored across northern Washington, Idaho, Montana, and into the northern Great Plains. This colder pattern fits with ongoing La Niña and an active Madden–Julian Oscillation (MJO) phase that encourages cold air intrusion.
• Sierra Nevada & Great Basin: Forecast confidence is lower here, with models showing “equal chances” in parts of California and Nevada. An active MJO could swing early‑month temperatures cooler than average, especially in higher elevations.
• Southwest (Arizona, New Mexico): Warmer than normal overall, especially in southern sections. Short cold snaps possible but less sustained chill than farther north.

Central and Eastern U.S.

• Northern Plains, Great Lakes, and Northern New England: Below‑normal temperatures likely, especially if a sudden stratospheric warming (SSW) event unfolds. Expect stronger intrusions of Arctic air in early and mid‑month.
• Southern Tier (California to the Southeast): Widespread warmth favored from southern California through the Gulf Coast into the Southeast and Mid‑Atlantic, with 50%+ probabilities for above‑average temperatures.

Alaska

• North Slope and Western Interior: Warmer than normal.
• Southeast Alaska (including coastal ranges and Juneau area): Cooler than normal, aligning with La Niña and MJO impacts.

NOAA December 2025 Precipitation and Snow Potential

Western Mountains

• Pacific Northwest to Northern Rockies: Above‑normal precipitation is expected from eastern Washington and Oregon into Idaho, western Montana, and Wyoming’s high country. This setup increases storm and snowfall prospects through early to mid‑December, especially in mountain zones like the Cascades, Bitterroots, and Tetons.
• California and Sierra Nevada: Forecast shows higher uncertainty, labeled “equal chances.” Early‑month conditions may stay variable depending on MJO evolution.
• Southwest (AZ, NM, southern CO): Below‑normal precipitation likely, reducing snowstorm frequency for areas such as the San Juans and southern Rockies.

Central and Eastern Ranges

Great Lakes Region & Northeast U.S.: Above‑normal precipitation signals suggest frequent storm tracks and potential lake‑effect snow bursts as Arctic air interacts with still‑warm lake waters.

Ohio Valley: Wetter than average; snow potential exists mainly north of the Ohio River as colder air deepens later in the month.

Alaska

Western and Northern Mainland: Wetter than normal, improving snow accumulation in northern ranges.

Southeast Alaska: Drier than normal under La Niña influence.

Key Takeaways for Ski Areas

Best bets for early‑season snow: Cascades, Northern Rockies, Tetons, and Northern Great Lakes.

Coldest air: Likely across northern U.S. states and mountain regions if an SSW develops by mid‑month.

More variable pattern: Sierra Nevada and Intermountain West, where MJO‑driven shifts could swing rapidly between warm and snowy spells.

Milder and drier zones: Desert Southwest, southern Rockies, and Southeast U.S.

The full discussion from the NOAA is below:

30-DAY OUTLOOK DISCUSSION FOR DEC 2025 
 
The December 2025 Monthly Outlook was made with ongoing La Niña conditions 
expected to continue into winter. The most recent weekly Niño 3.4 sea surface 
temperature (SST) anomaly is about -0.7 degrees Celsius. SST anomalies in the 
central and east-central equatorial Pacific Ocean remain negative. Outgoing 
longwave radiation (OLR) anomalies were negative over the far western Pacific 
Ocean, associated with enhanced convection and precipitation over parts of the 
Maritime Continent. Positive OLR anomalies, indicating suppressed convection 
and precipitation, were present near the International Date Line, consistent 
with La Niña conditions. Low-level (850-hPa) easterly trade winds were enhanced 
over the western and east-central equatorial Pacific, also consistent with La 
Niña conditions. Upper-level (200-hPa) wind anomalies were westerly over most 
of the equatorial Pacific Ocean in recent weeks. Negative subsurface ocean 
temperature anomalies persisted near the surface in the central and eastern 
equatorial Pacific Ocean, increasing the likelihood of persistent La Niña 
conditions. Dynamical model forecasts and the CPC El Niño Southern Oscillation 
(ENSO) Outlook predict La Niña conditions are most likely to persist for the 
December-January-February winter season with a probability slightly greater 
than 50 percent. However, La Niña conditions are most likely to end in the 
January-February-March season with a probability greater than 60 percent. 
Although this La Niña is likely to remain weak and be of short duration, 
predictability of the December climate outlook is largely due to current La 
Niña conditions. 
 
Recently, the upper-level polar vortex has become displaced from the pole and 
elongated over North America. Recent forecasts from the ECMWF model predict 
enhanced probabilities of a rare November sudden stratospheric warming (SSW), 
and propagation of atmospheric temperature anomalies to the surface in polar 
regions, resulting in a negative Arctic Oscillation (AO). Forecasts of the 
potential SSW event remain uncertain and change from model run to run. Although 
there is still substantial uncertainty, an SSW could greatly impact the climate 
outlook for December over North America. 
 
The Madden Julian Oscillation (MJO) has recently been active with enhanced 
convection currently over the far Western Pacific Ocean. Dynamical models  such 
as the ECMWF predict the potential propagation of the MJO signal eastward into 
the Western Pacific. The MJO in this phase enhances the chances of cold air 
intrusion into the north-central contiguous United States (CONUS) in early 
December extending into the Northeast with time. The combined influence of the 
MJO, La Niña, and a possible SSW were considered in the December climate 
outlook. 
 
The December temperature and precipitation outlooks were based primarily on 
dynamical model and statistical model forecasts. Dynamical model forecasts for 
the month of December are from the North America Multimodel Ensemble (NMME). In 
addition to the NMME, a consolidation of model forecasts was utilized, which 
includes the following statistical tools: the Canonical Correlation Analysis 
(CCA), the Constructed Analog (CA), and an ENSO OCN tool, that combines the 
impact of ENSO, based on the CPC SST consolidation predicted median Niño 3.4 
SST anomaly, with the Optimum Climate Normal (OCN) to represent decadal trends . 
Daily initialized forecasts from the Climate Forecast System (CFSv2) dynamical 
model for the month of December and the most recent ECMWF and GEFS dynamical 
model forecasts for the week 3-4 period that overlaps the beginning of the 
month of December were also considered. Recent boundary conditions, including 
coastal SSTs, and soil moisture anomalies, were additional factors considered 
in the outlook. 
 
The December outlook favors above normal temperatures for the eastern 
Aleutians, western Mainland Alaska, and the North Slope, consistent with 
dynamical model guidance from the NMME and CFSv2, as well as decadal climate 
trends. Below normal temperatures are favored for parts of southeastern 
Mainland Alaska and Southeast Alaska, consistent with dynamical model forecasts 
from the NMME and CFSv2, as well as the combined impacts of La Niña and the 
predicted propagation of the MJO into the Western Pacific. The temperature 
pattern over the CONUS in the December outlook is consistent with the La Niña 
base state modified by the impacts of MJO and a potential SSW. Above normal 
temperatures are favored across the southern tier from California, across the 
Southwest, into the Gulf Coast region and Southeast. Probabilities exceed 50 
percent over parts of the Desert Southwest and Rio Grande valley, consistent 
with recent temperature forecasts from the CFSv2, the consolidation, and 
decadal trends . Probabilities for above normal temperatures for this region are 
also enhanced by the correlation between predicted below normal precipitation 
and above normal temperatures. Probabilities for above normal temperatures over 
much of California and Nevada are reduced, due to uncertainty related to an 
active MJO and ECMWF and GEFS forecasts for the first half of the month that 
show weak signals  over much of the West. Probabilities favoring above normal 
temperatures over the Southeast and parts of the Mid-Atlantic coast are 
consistent with the impacts of La Niña. Below normal temperatures are favored 
for the northern CONUS from northern Washington across the Northern Rockies 
into the northern Great Plains, the Great Lakes region, and along the Canadian 
border of the Northeast, based on recent forecasts from the CFSv2 model for 
December, as well as forecasts for the first half of December from the ECMWF 
model. The predicted temperature pattern is largely consistent with the 
combined influences of La Niña and MJO propagation into the Western Pacific. 
Development of an SSW would substantially increase the probabilities of below 
normal temperatures over the central CONUS. 
 
The December outlook favors above normal precipitation for the eastern 
Aleutians, western Mainland Alaska, and parts of the North Slope, consistent 
with the consolidation of dynamical and statistical model precipitation 
forecasts and decadal trends . Below normal precipitation is favored for the 
southeastern coast of Mainland Alaska including Southeast Alaska, consistent 
with dynamical model forecasts for December, La Niña, and impacts of a Western 
Pacific MJO. Above normal precipitation is favored over much of the 
northwestern CONUS from eastern areas of the Pacific Northwest to the northern 
High Plains, consistent with the CFSv2 forecast for December and the ECMWF 
forecast for the first half of the month. Equal Chances (EC) of above and below 
normal precipitation is indicated closer to the coast of the Pacific Northwest, 
where the December consolidation forecast and the CPC Week 3-4 Outlook indicate 
uncertainty in the precipitation signal. Above normal precipitation is also 
favored for the Ohio Valley, Great Lakes region, and Northeast, consistent with 
dynamical model forecasts for the first two weeks of December and possible 
impacts of an active MJO in the Western Pacific and a potential SSW. Below 
normal precipitation is favored for eastern areas of the Southwest, including 
parts of Arizona, New Mexico and Texas, and for parts of the Southeast Gulf and 
Atlantic coasts, consistent with canonical impacts of La Niña and predicted by 
the NMME and consolidation forecasts. There is greater uncertainty, indicated 
by EC, in the precipitation outlook for California and western areas of the 
Southwest. 
 
FORECASTER: Dan Collins