What Kp do I need to see the aurora?

It depends on how far north you are. Over northern Scandinavia, Iceland and northern Canada Kp 2 or 3 is often enough on a dark night. Around 55 to 60 degrees north you usually need Kp 5 or more, and further south Kp 7 or more.

Is the aurora layer free?

Yes. Create an account, enter your SimBrief Pilot ID and the Aurora row is in the Layers panel of the enroute map. You can try the map first with the demo flight.

How often is it updated?

NOAA updates the aurora forecast about every five minutes and the Kp estimate every minute. SkyNexus fetches both at most every 10 minutes, which is well within how fast the forecast changes.

Does a high Kp affect my flight in the sim?

Not unless your simulator or network models it. On VATSIM and in MSFS or X-Plane, HF and GPS keep working as normal. The layer is there for realism and planning: it tells you what a real crew on your route would be dealing with, and where the northern lights are tonight.

Does it cover the southern hemisphere?

Yes. The layer shows the aurora australis around Antarctica too, for flights between Australia, New Zealand, South America and South Africa.

Space weather

Kp index and aurora on your route

The Kp index says how disturbed the Earth's magnetic field is, on a scale from 0 to 9. The higher it is, the further from the poles the aurora reaches and the more high-latitude radio and navigation can suffer. SkyNexus shows the NOAA aurora forecast as a green layer on the enroute map, with the current Kp next to it, so you can see whether a night flight over the North Atlantic, Scandinavia or Canada will pass under the northern lights.

Kp now0.0quiet, aurora mostly near the polesEstimated planetary Kp from NOAA SWPC, 22:25 UTC. Refreshed every 10 minutes.

What the Kp index is

Kp is a planetary index built from magnetometers around the world. Each value covers three hours, and NOAA also publishes an estimate every minute. Kp 0 to 3 is quiet, Kp 4 is active, and from Kp 5 NOAA calls it a geomagnetic storm on its G scale: G1 at Kp 5 up to G5 at Kp 9.

On a quiet night the aurora sits in an oval around the magnetic poles, over northern Norway, Iceland, southern Greenland, northern Canada and Alaska. As Kp rises the oval widens towards the equator. Around Kp 7 it can reach northern Germany, the Netherlands and the northern United States.

Why it matters on a real flight

Aircraft over the oceans and the poles use HF radio for position reports when they are out of VHF range. During geomagnetic storms HF can fade or drop out at high latitudes, and satellite navigation can lose some accuracy. Crews on polar and North Atlantic routes check space weather for this reason, and during strong storms airlines may plan polar flights further south.

Radiation exposure at altitude is a separate matter. NOAA reports it on its S scale for solar radiation storms, not with Kp, so a high Kp alone does not mean a radiation warning.

Kp 0 to 4: no effect a pilot would notice, aurora at high latitudes only.
Kp 5 to 6: HF can be patchy at high latitudes, aurora visible further south.
Kp 7 and above: HF and GNSS problems are more likely on polar routes, aurora possible over central Europe and the northern US.

The view from the flight deck

From cruise you are above most cloud, so an aurora that is hidden from the ground can be in full view. Look north from the northern hemisphere, and it has to be dark: a night flight between Europe and North America, or towards Asia over Scandinavia and Russia, has the best chance. Whether your simulator draws an aurora depends on the sim. The layer shows where the real one is forecast, which is a good reason to plan a night flight that way.

The aurora layer in SkyNexus

Open the Layers panel on the enroute map and switch on Aurora in the Weather group. The green shows the chance of visible aurora from the NOAA OVATION model, which looks about half an hour to an hour and a half ahead from the solar wind measured upstream of the Earth. Pale green is a small chance, stronger green a higher one. The row shows the current estimated Kp, and hovering it tells you what that Kp means.

Off by default, so it stays out of the way until you want it.
Refreshed every 10 minutes while the layer is on.
Drawn under the route, airways and weather, so it never covers what you fly by.

Where the data comes from

Both the aurora forecast and the Kp come from the NOAA Space Weather Prediction Center. SkyNexus reads them on its own server and does not change them, apart from thinning the aurora grid to what a map needs.

NOAA SWPC aurora forecast for the source product.
NOAA SWPC planetary K-index for the Kp history.

Kp and aurora FAQ

What Kp do I need to see the aurora?: It depends on how far north you are. Over northern Scandinavia, Iceland and northern Canada Kp 2 or 3 is often enough on a dark night. Around 55 to 60 degrees north you usually need Kp 5 or more, and further south Kp 7 or more.
Is the aurora layer free?: Yes. Create an account, enter your SimBrief Pilot ID and the Aurora row is in the Layers panel of the enroute map. You can try the map first with the demo flight.
How often is it updated?: NOAA updates the aurora forecast about every five minutes and the Kp estimate every minute. SkyNexus fetches both at most every 10 minutes, which is well within how fast the forecast changes.
Does a high Kp affect my flight in the sim?: Not unless your simulator or network models it. On VATSIM and in MSFS or X-Plane, HF and GPS keep working as normal. The layer is there for realism and planning: it tells you what a real crew on your route would be dealing with, and where the northern lights are tonight.
Does it cover the southern hemisphere?: Yes. The layer shows the aurora australis around Antarctica too, for flights between Australia, New Zealand, South America and South Africa.

See the aurora on your next night flight

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