Pick the resorts you're weighing up and the dates you can travel. Every figure is what those days actually delivered at the nearest official weather station, season after season — history, not a forecast.
Pick as many as you like. Resorts sharing one weather station — Asahidake and Kamui both read from 旭川 — will show identical numbers.
Every figure on this page is an observation from one of these stations — never a resort's own marketing number. Stations sit in the valley town rather than on the mountain, so the gap below the summit is the main reason on-hill totals run higher.