Know what the mountain
will feel like to you.

One mountain. It rained last night, then cleared and froze hard before dawn. At 1 PM it’s 35°F.

A weather app shows the same 35°F either way. Here’s what the snow does:

Same mountain, same temperature, a 4.7-point difference. The weather alone can’t tell you that. What happened to the snow can.

The model, by the numbers

6forecast models blended

ECMWF, GFS, Canadian, ICON and UK Met Office, plus the HRRR in the lower 48.

25weather readings an hour

15 at the slope, plus air temperature at 10 heights above it.

3elevations

Base, mid and summit, each modeled on its own.

120hours of past weather

Replayed hour by hour before we score today.

20+snowpack traits tracked

New snow, wetness, crust, pack temperature, traffic.

17settings you control

11 surfaces, 5 kinds of weather, your perfect temp.

The five things that move a score most

1. 1Sun on the snowIn watts, not just “sunny”. March sun turns a crust to slush at 35°F; January sun barely touches it.
2. 2Temperature, in the air and in the snowAt all three elevations. The snowpack lags the air by hours, so a warm morning after a cold night still rides firm.
3. 3Cloud cover overnightA clear night refreezes the snow far harder than the low suggests. Cloud acts like a blanket.
4. 4New snow, and how dry it isSized from the warmest air the flakes fall through, so cold storms make light powder and warm ones heavy snow.
5. 5RainIt soaks into the pack and refreezes into ice. Humidity tells us if a 33°F hour is rain or snow.

Also weighed: wind, dew point, snow depth, ground temperature, and day versus night.

How we read the past five days

Every forecast starts five days ago. We run the snow model through every hour since, at all three elevations, so today starts from what actually fell, melted and froze rather than a guess. It remembers:

• Every inch of new snow, how dense it was, and how old it is
• Every rain, thaw and refreeze, and how hard each one set
• The crust underneath, the sun the snow has soaked up, and how cold it is inside
• How many hours of lift traffic have chopped it up

Customized the second you save

The snow physics is the same for everyone. What changes is what each surface is worth to you.

With a season pass, rate 11 surfaces from powder to ice, say how you feel about snow, sun, cloud, rain and sleet, and name your perfect temperature.

Hit save and every hour at every mountain is rescored your way on the spot: scores, best window, best day and alerts. A slush lover and a groomer rider get a different best day, and they should.

How we keep ourselves honest

No model gets more than 40% of the say, and when they disagree about a storm we say low confidence instead of picking one. Every day we check our forecasts against 17 real weather stations near ski areas.