Idaho Winter Forecast 2026–27: Snow, Cold & First Snow
Typical first snow November 25 · Boise averages 18 in a season — plus NOAA's Dec–Feb outlook for the state and what's on the ground right now.
First snow typically November 25 · 48 days awayThe Idaho snow season at a glance
NOAA 1991–2020 normals · BoiseBoise's "Snowpocalypse" of 2016–17 (39 in, double normal) collapsed roofs across the Treasure Valley — while the Panhandle 300 miles north treats that as an ordinary winter.
What NOAA's 2026–27 winter outlook means for Idaho
NOAA's Climate Prediction Center issues a probability tilt — above, below, or equal chances — for temperature and precipitation, three months at a time. It is the only government seasonal forecast that exists, and it does not, and cannot, forecast snowfall totals or specific storms.
Where this tilt comes from: Each state's tilt here is read straight off CPC's official Dec–Feb probability map, at the three reference cities listed on that state's page. CPC forecasts by region, not by state: its probability bands cross state lines, so where a state's three cities land in different bands the tilt shows as equal chances. Check any state against CPC's own map. See CPC's official Dec–Feb outlook map →
What it means for snow: A milder tilt with no precipitation lean usually means snowfall slightly below normal — fewer days cold enough for snow, not necessarily fewer storms.
Rockies context. Mixed, and split north to south. Montana is the one state in the region favored both milder and drier — the worst combination for snowpack — while Idaho and Wyoming lean milder with equal chances on precipitation. Colorado goes the other way: equal chances on temperature but a tilt toward above-normal precipitation, consistent with a southern-branch storm track that has historically done more for Colorado's southern mountains than its northern ranges. Utah is equal chances on both. Nevada leans milder and wetter.
Snow on the ground in Idaho right now
| City | Snow depth now | Snowfall next 7 days | Coldest low next 7 days | Normal season |
|---|---|---|---|---|
| Boise | loading… | — | — | 18 in |
| Idaho Falls | loading… | — | — | 35 in |
| Coeur d'Alene | loading… | — | — | 50 in |
Loading live conditions…
Snow depth map around Boise
Current modeled snow depth across the surrounding terrain, or flip to the 7-day snowfall forecast. Enter a ZIP to recenter anywhere in the country.
Modeled snow depth on the ground around Boise, ID. This is a weather-model estimate, not a gauge reading: it misses drifts, shaded hollows, and freshly plowed lots. For official observations see NOAA's NOHRSC snow analysis or a nearby SNOTEL site.
Boise winter normals, October–April
| Month | Avg snowfall | Avg high | Avg low |
|---|---|---|---|
| October | 0 in | 65°F | 41°F |
| November | 2 in | 50°F | 32°F |
| December | 6 in | 39°F | 26°F |
| January | 7 in | 38°F | 25°F |
| February | 3 in | 45°F | 28°F |
| March | 1 in | 55°F | 34°F |
| April | 0 in | 63°F | 39°F |
NOAA NCEI 1991–2020 climate normals for Boise, rounded. Seasonal total (18 in) includes May–September trace months not shown. January is the snowiest month. State record low: -60°F, Island Park Dam, 1943.
Idaho's snow belts
Panhandle
Schweitzer & Silver Mountain
Sawtooths & Sun Valley
One of Idaho's snowiest zones — expect totals well above the Boise normal.
Teton Valley / Driggs
One of Idaho's snowiest zones — expect totals well above the Boise normal.
Island Park plateau
One of Idaho's snowiest zones — expect totals well above the Boise normal.
Idaho winter-prep checklist, by date
The first frost is the warning shot. Typical first frost in Idaho: September 28 — see the Idaho first-frost page.
A hard freeze typically follows the first frost by about two weeks. Backflow preventers and above-ground manifolds crack first — this is the single most expensive thing to skip.
Book the HVAC tech before the first cold snap, when every company's schedule fills. Test the CO detector — furnaces and generators are the two winter CO sources.
Median first measurable snow in Boise is November 25; one winter in ten it arrives by November 5.
With a normal January low of 25°F, Idaho homes are built for cold — the risk is the unheated garage, crawlspace, or vacation property.
Ice storm risk in Idaho: low
Idaho rarely sees damaging freezing rain. Where ice is a problem it is black ice on roads after a thaw-refreeze, not accumulation on lines and trees.
Freezing rain needs a specific sandwich: warm, moist air aloft sliding over a shallow layer of below-freezing air at the surface. That is why the ice belt runs from Texas and Oklahoma through the Ozarks, the mid-South, and up the Carolina Piedmont into the mid-Atlantic — places where arctic air arrives thin and Gulf moisture arrives on top.
What a seasonal outlook tells you about snow
Day-to-day weather is unpredictable beyond about two weeks. What seasonal forecasters have instead is the background state — mainly ENSO, the El Niño / La Niña cycle in the tropical Pacific — which nudges the jet stream's average position for months at a time. NOAA's Climate Prediction Center turns that nudge into a probability: "40% chance of above-normal temperatures" means 40%, with 33% the climatological baseline. A 33/33/33 split (equal chances) means they see no usable signal at all.
Snowfall is harder still, because it needs cold and moisture to line up storm by storm. A warm, wet tilt can deliver a huge snow winter if the cold arrives on the right three days, or a washout if it doesn't. Independent verification studies consistently find CPC temperature outlooks carry modest skill in winter (most of it from ENSO and long-term warming trends), precipitation outlooks less, and almanac-style snow forecasts none. So: use the tilt to lean your planning, use the 30-year normals on this page as the anchor, and use the 7-day forecast for anything that actually needs a decision.
This year's background state: El Niño conditions are present and strengthening. In its August 13, 2026 ENSO Diagnostic Discussion, CPC gave a greater than 90% chance of a very strong event during fall and winter 2026–27, and a 69% chance that the October–December season sets a record (+2.5°C or more, 3-month RONI) for any El Niño since 1950. CPC is explicit that impacts consistent with El Niño become more likely with an event this large, but are not guaranteed.
- A stronger, southward-shifted Pacific jet stream: wetter than normal across the southern tier from California to the Southeast, especially in late winter (Jan–Mar).
- Milder than normal across the northern tier — Pacific Northwest, northern Rockies, northern Plains, Great Lakes, and Northeast — with below-normal snowfall often following from the warmth, not from a lack of storms.
- Drier than normal across the northern Rockies, northern High Plains, and parts of the Great Lakes and Ohio Valley; mainland Alaska trends drier and milder.
- Nor'easters and Gulf-coast storms are often more frequent in strong El Niño winters; whether they fall as snow or rain in the mid-Atlantic is the big unknown and depends on the cold supply week to week.
- Ice-storm risk climbs in the Southern Plains and Southeast when a wet southern storm track meets shallow cold air — exactly the setup strong El Niño favors.
Idaho winter forecast FAQ
More Idaho seasonal timing
More Rockies winter forecasts
Climatology: NOAA NCEI 1991–2020 U.S. Climate Normals for Boise and the cities listed; state record lows from NCEI state climate extremes. Outlook: NOAA Climate Prediction Center seasonal outlook issued August 20, 2026 — a probability tilt, not a snowfall forecast, and the state-level tilt shown here is taken from CPC's official Dec–Feb probability map at each state's three reference cities, since CPC publishes probabilities by region rather than a call per state. Live values: Open-Meteo model data, not gauge observations. Hero image: “Rime ice on Jay Peak” by Runningonbrains, CC BY 3.0. National picture: the 2026–27 winter outlook for every state → · national snow depth map →