About Aurora Tonight
Aurora Tonight is a live aurora forecast dashboard built for aurora chasers, night photographers, and travellers who want a fast, specific answer to one question: is the aurora likely to be visible from where I am standing, tonight?
What the site does
The dashboard pulls real-time and short-range forecast data from the NOAA Space Weather Prediction Center (SWPC) — the planetary Kp index, solar wind speed and density, the interplanetary magnetic field's north-south component (Bz), and NOAA's OVATION auroral oval model — and turns it into plain-language guidance: current conditions, a short outlook, and a personal verdict for a location you choose.
How the "tonight" verdict is computed
The verdict shown on the Tonight page is computed entirely in your browser from three inputs:
- Your geomagnetic latitude. Visibility of the aurora tracks geomagnetic latitude, not geographic latitude, so your location is converted before anything else happens.
- The Kp threshold for that latitude. Each geomagnetic latitude band has an approximate Kp index at which the auroral oval typically expands far enough to become visible overhead or on the horizon. The current and forecast Kp are compared against that threshold.
- A cross-check against NOAA's OVATION model. Kp is a coarse, planetary-scale number, so the threshold estimate is cross-checked against NOAA's higher-resolution OVATION auroral oval product where it is available, and reconciled with whether your location is currently in astronomical darkness — a numerically favourable Kp is meaningless at local noon or under a full daylight sky.
None of this involves a server-side lookup of who or where you are. See Privacy for the specifics.
What it doesn't do
It doesn't check cloud cover, and it isn't a substitute for judgement about travel, safety, or spending money to chase a forecast. See the Disclaimer for the full list of limitations — they're worth reading before you book a trip around a forecast.
Why it exists
NOAA's own data products are excellent but built for a general audience — space weather forecasters, ham radio operators, satellite operators — not specifically for someone standing outside wondering whether to keep watching the sky. Aurora Tonight exists to answer that narrower question quickly, on a phone, in the cold.
For the full list of upstream data products and how often each one refreshes, see Data sources.