Enter a 4-character code for the live report, or paste a whole METAR. Esc closes.Tap outside to close.
How this is drawn
The sky is computed in a WebGL2 fragment shader from the report below it. It is an honest approximation, not a photograph: the amounts, heights, visibility, wind and sun come from data; shapes and colours are a model.
From this report
Style choices, not data
Cloud shapes are procedural noise. A METAR gives only how much of the sky is covered and the height of the cloud base; thickness and style (heaped, flat, streaky) are chosen from that height.
Colours come from a simplified single-scattering atmosphere with a rough multiple-scattering term, then a film-like tone curve.
Stars are decorative and randomly placed, not a star map. There is no moon yet.
At night, low cloud and fog get a faint warm glow from below, standing in for airport and city lights. That is an assumption; the report says nothing about it.
The ground is a plain dark plane, not the real terrain, seen from about 25 m up, roughly a control-tower cab. With a low sun the view faces the sun's side of the sky, so sunrise, sunset and twilight are in frame; with a high sun it faces away, so clouds are lit from the front. The label gives the viewing bearing (VIEW).
Where the sky is bright, it is dimmed toward the corner and edge the text sits against, like the shadow of a window frame, so the words stay readable.
Sources
Live reports: the Aviation Weather Center Data API (aviationweather.gov), NOAA / National Weather Service. Public US-government data. Station position also comes from that API.
Sun position: NOAA's solar position equations (after Meeus, Astronomical Algorithms).
Haze: Koschmieder's relation between visibility and extinction.
Recorded samples (bundled, so the page works offline): real reports from the same API, recorded on 26 Sep 2026. Versions, licences and sources of everything bundled: third-party notices.