MeteoSwiss's own models, taken seriously. ICON-CH1 is a 1 km ensemble over Switzerland and the Alps, refreshed eight times a day, and MeteoSwiss publishes all of it openly. Almost nobody outside the institute draws it. This site makes it the flagship, with ICON-CH2 carrying the same physics to five days and DWD's ICON-EU and ECMWF's IFS beside them for the longer range and an independent opinion.

Every model is corrected onto the same terrain. This is the thing that makes the site worth having. At 9 km ECMWF puts Zermatt's valley floor at 2,903 m where the truth is 1,608, and draws it seven degrees too cold as a result; Säntis's 2,502 m summit reads as 1,097 m and comes out seven degrees too warm. Drawn raw and flipped between, the maps would differ mostly in orography. Corrected onto ICON-CH1's own 1 km surface, a difference between the tabs is a real disagreement about the weather. Measured against that model over 23 Swiss stations, the correction takes mean error from 3.13 K to 1.39 K.

Four fields exist because this is Switzerland. The snow line and the SWISS12 thunderstorm index are computed by MeteoSwiss and shipped in the open data — the snow line is a proper wet-bulb boundary, not a freezing level with an offset subtracted, which matters because in dry air the two are hundreds of metres apart. Föhn and inversion are derived here: the first from a cross-Alpine pressure gradient, the across-crest wind and the downslope terrain together, the second from the model's own vertical stratification.

Absolute colour scales, and a value under every pixel. Ramps are pinned to real numbers, so a loop shows intensity changing rather than a palette re-fitting itself each frame. The frames are palettised PNGs and the catalog ships the same table, so hovering reads the colour back to a number without fetching anything extra.

Not an official MeteoSwiss service, and not a source of weather warnings — for those, MeteoSwiss is always the authority. MeteoSwiss data under CC BY; DWD and ECMWF under CC BY 4.0.