Where JapanSnowWatch gets resort details, weather, snow depth, webcams and opening dates, how often each one changes, and who checks them.
This page lists the source of each kind of data on JapanSnowWatch and how often it changes. Corrections go to [email protected].
Resort names, locations, lifts, runs, vertical drop and contact links come from each resort's official website and published resort material. A figure that has not been checked against that material is labelled Estimated, and the rankings either leave it out or mark it.
Lift ticket prices come from the resort websites and show the season they apply to. Resorts that have closed or suspended operations are recorded with the source that reports it and are left out of the resort lists and counts.
Forecasts, current conditions and modelled snow depth come from Open-Meteo, requested for each resort's coordinates (rounded to about 11 km). The seven-day forecast is cached for up to six hours and the 16-day detailed forecast for up to four, so a figure can be that old when you see it. Past snowfall comes from the Open-Meteo archive.
These are model values, not readings from the resort's own snow stake, and they can differ from what a resort reports. Where a resort page links to the Japan Meteorological Agency, that is the official forecast. The prefecture snowfall averages on the snow forecast page are drawn from JMA climate normals and resort-published season averages.
The snow quality score is calculated from the next 48 hours of forecast temperature, wind, rain, freezing level and new snow.
The cameras are published by the resorts, their operators and camera services such as SkiCast. JapanSnowWatch embeds or links to those feeds; it does not run its own cameras. Some play only on the resort's own site, and those open there.
A LIVE badge appears only on live-feed cameras, and only while the resort's season is running. Cameras that stop working upstream are marked unavailable in the data and are hidden until they come back.
The 2026-27 opening dates on the season calendar are checked one resort at a time. Each row links to the page that shows the date, which is the resort's official page where one exists. A news report is used only when the resort has published nothing, and that row is marked as news.
A date is entered only when the source gives it. A source with a full date is shown as announced, one with only a month as planned, and one with nothing for 2026-27 as not yet announced. A closing date is added only when the same source gives it.
Each row records the day its source was last opened, and the calendar's Last checked date is the newest of those. Last season's opening date is shown only as last season's.
David, the editor, writes the blog posts, checks each opening date on the season calendar against the resort's official announcement, and runs the site's Instagram account.
Some text is drafted and translated with AI tools.