Single-source apps smooth this valley flat. We blend several models, correct them to the lakeside station using our own daily verification record, and show our work — the spread, the confidence, and where the models miss.
Each day is the multi-model blend, corrected to the lakeside station. When a correction moves a number 2° or more you'll see the raw model value struck through beside it, so you always see what we changed and why.
From the Vallecito Dam cooperative weather station, with a record going back over a century.
The bold line is the valley forecast; the shaded band is how far the models disagree. Drag across it — or focus it and use the arrow keys — to read any hour.
Drag or use ← → · the band is model spread, the line is the corrected blend.
The latest radar frame over the San Juans (RainViewer). Loads when you scroll here to keep the page light.
Radar © RainViewer · base map © CARTO/OpenStreetMap · data NOAA/NWS.
The lake sits at about 7,665 ft; Big Bear Park (station BBRC2) is up at 10,341 ft, ≈2,700 ft higher toward the Weminuche. The difference between them is the gradient that flat forecasts miss.
US AQI & PM2.5 from the Open-Meteo Air-Quality API. Wildfire smoke can change this fast in summer.
How it is scored against reality, what any model struggles with here, and why it disagrees with your phone. Open it if you want the workings.
Every morning we compare yesterday's forecast to the lakeside station and keep the record — public from day one. This is the trailing 30 days.
Patterns we only trust once the valley's own record proves them. Each appears here with its evidence count, and never before it clears at least 20 cases.
Most apps read one model and smooth the terrain flat. We pull several — NWS, GFS, ECMWF, ICON — pin them to the lake's real elevation, and blend them. Then the honest part: every morning we score yesterday's forecast against the marina's lakeside station and file the result. Once a pattern proves itself over at least 20 days, and only then, we start correcting for it automatically — clear-night cold-air drainage, afternoon up-valley wind, the elevation gradient. Until a correction earns its place it stays off and we show the raw blend. No black box and no fake precision: a range, its confidence, and a scoreboard you can check.
Sources: —. · Ground truth: the lakeside marina station. See how we verify.