Weather forecasts

The source

Every score comes from Open-Meteo, a free weather service, under CC BY 4.0.

Which weather model

• Canada: the Canadian GEM models, which start with a detailed 2.5 km model for the first two days, then regional and global ones.
• United States: Open-Meteo's best match for the location, drawn from NOAA's models.

Which elevation

• Downhill: two forecasts, at the base and the summit, averaged into one for mid-mountain.
• Classic, skate and snowshoe: one forecast, at the area's mid elevation.
• No elevation in the listing: the model's own height for that spot.

What's fetched

9 values for every hour: temperature, snowfall, rain, all precipitation, wind, gusts, cloud cover, snow depth and sunshine. That covers 7 days back and 5 days ahead. The daily figures are worked out on your phone from the hours.

How fresh it is

Forecasts are fetched when you open the app, when you come back to it after 3 hours, and straight away for a place you've just saved. Each place shows its forecast's age, which turns gold after 6 hours. A request that hasn't answered within 15 seconds is dropped and the forecast you had is kept.

How accurate is it?

Mountain weather is hard to forecast. A model averages over valleys and peaks, snowfall amounts and freezing levels can be off, and each day further ahead is less certain. Treat the scores as a forecast: check the webcam and the operator's snow report, especially before a long drive. If a day turned out very differently, Not right? with "The weather was different" helps check the forecast.

Missing values

A value the forecast doesn't have is never taken as zero, so a failed download can't look like "0 cm of new snow". A day missing something the score needs isn't scored, and shows a dash (—).