Forecast tools · live SWPC data
Live aurora map: the OVATION oval around your town
The same model SWPC draws for the whole pole, turned so that your town sits under it, with the circle of sky you can actually see.
Tonight at Minneapolis, MN
…
Reading the SWPC Kp forecast and the cloud forecast…
| Kp forecast during the dark hours | not yet forecast |
|---|---|
| Kp needed here | 5.9 (G2 moderate) |
| Cloud cover in the dark hours | loading |
| Dark sky (Sun 18° down) | 8:08 PM to 5:50 AM CDT |
| Moon | 13% lit |
| Right now, OVATION (30 to 90 min) | loading or unavailable |
| Magnetic latitude (AACGM) | 54.2° |
Hour by hour, CDT
7 PM
Kp –
– ☁
No
8 PM
Kp –
– ☁
No
9 PM
Kp –
– ☁
No
10 PM
Kp –
– ☁
No
11 PM
Kp –
– ☁
No
12 AM
Kp –
– ☁
No
1 AM
Kp –
– ☁
No
2 AM
Kp –
– ☁
No
3 AM
Kp –
– ☁
No
4 AM
Kp –
– ☁
No
5 AM
Kp –
– ☁
No
6 AM
Kp –
– ☁
No
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OVATION is the model behind the oval maps of the NOAA Space Weather Prediction Center. It takes the solar wind speed and magnetic field measured at the L1 point, about 1.6 million km upstream of Earth, and turns them into a probability, from 0 to 100%, of seeing aurora overhead at every one-degree point of the globe for the next 30 to 90 minutes, the time it takes the wind to reach us. This page draws that grid on a polar view turned toward your town and adds what the SWPC map does not: a dashed circle of 500 km around you, the distance at which aurora sitting 100 km up still stands about 9 degrees above the horizon. The figure in the result card is the highest probability inside that circle, the number that matters for your sky right now.
Where the map comes from
The OVATION Prime model was developed at the Johns Hopkins University Applied Physics Laboratory by Patrick Newell and co-workers and put into real-time service by NOAA in 2011, as the SWPC aurora page recounts. It estimates the flux of electrons and protons falling into the atmosphere, then converts that energy into a viewing probability. SWPC publishes the result every few minutes as a grid of 360 by 181 points (OVATION JSON), which this page downloads in your browser, about one megabyte, and redraws.
The projection is azimuthal equidistant centred on the geographic pole, with parallels every 10 degrees from 30 to 80 north, and it is rotated so that your longitude points down. Land comes from the Natural Earth 1:110 million outline. No interpolation is added: each colored square is one cell of the SWPC grid.
Why a circle of 500 km
The aurora is high: SWPC puts it between 80 and 500 km, with the common green light from about 120 km up. Light that high is visible from far away, and SWPC notes that a bright display can be seen up to 1,000 km away from a good vantage point. We use half of that as the everyday reach: at 500 km, the lower edge of an aurora 100 km up stands about 9 degrees above a flat horizon, high enough to clear trees and haze. At 1,000 km it would sit about 1.2 degrees up, which only an open sea or prairie horizon allows. The colors guide lets you try other distances.
Reading the map in practice
Look for two things. First, the position of the equatorward edge of the colored band against your dashed circle: if the band touches the circle, aurora is within reach of your sky. Second, the time printed under the map: OVATION is a nowcast, and a run that is an hour old describes conditions that may already have changed. Reload during a storm; the grid refreshes every few minutes. A band that suddenly thickens and brightens on the night side of the pole is the signature of a substorm, often the best twenty minutes of the night, and the moment to step outside if your circle is close to the green.
Limits of the map
OVATION is a statistical model: it reproduces how the aurora usually responds to a given solar wind, not the exact shape of tonight's arcs. It tends to be smoother than reality, missing the bright folds of a substorm and sometimes the far southern reach of a big storm. Its probabilities are for a dark, clear sky; the map knows nothing of the Sun or the clouds over you. Use it for the next hour, and the three-night forecast for anything later.