About
Borealis Radar · PublishedWhat is Borealis Radar?
Borealis Radar is a free, real-time aurora visibility tool. It pulls together the half-dozen data feeds that astronomers and aurora chasers actually look at — Kp index, IMF Bz, OVATION model, solar wind speed, cloud cover, moon phase — and turns them into one number: your chance of seeing the northern lights tonight, from where you are right now.
The radar updates continuously. There's no login, no signup, no email gate, no ads, no analytics, and no upsell. It's just a tool I wanted to exist.
Why I built it
Most aurora forecasts are either too technical (raw NOAA bulletins with magnetometer charts) or too vague ("activity is moderate tonight"). I wanted something that answers the actual question — should I drive out to a dark-sky spot? — for a specific location, in plain language, in under three seconds.
Borealis Radar combines NOAA's space weather products with local cloud cover and moon illumination, weights them the way an experienced observer would, and shows you the result with a verdict: Exceptional, Good, Possible, Camera Only, or Unlikely.
Data sources
- NOAA SWPC — Kp planetary index, IMF magnetic field components, solar wind plasma data, and the OVATION auroral oval model. Updated every 1–5 minutes.
- OpenWeatherMap — cloud cover layer for the map and your local cover percentage.
- Open-Meteo / browser geolocation — your position, used only to fetch local conditions (never stored).
- OpenStreetMap — base map tiles via Leaflet.
Methodology, in one paragraph
The visibility score is a weighted blend of solar wind energy input (Kp + Bt + wind speed + Bz direction), the OVATION auroral oval probability for your latitude, the local cloud-cover penalty, the moon-illumination penalty, and a daylight gate (no aurora visible during civil twilight or brighter). Each ingredient is published in the panel so you can see why the verdict is what it is — no black box.
Source & licensing
Borealis Radar is privately developed. Reach out via the in-app Feedback button if you'd like to collaborate, contribute translations, or report inaccuracies in the methodology.