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Skyfold Aurora Outlook

Chance of seeing the northern or southern lights at your place for the next three nights.

Decimal degrees such as 52.09, 5.12 (north and east positive), or DMS, UTM, MGRS, Maidenhead or a plus code.

m

IANA name such as Europe/Berlin or America/New_York, or a fixed offset such as UTC+2.

More options

The NOAA “3-Day Forecast” text or the planetary K-index forecast JSON.

Only with the fetched forecast; the place is rounded to 0.01° for the request.

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Try an example: ·

More about this tool

How it works

Combines the NOAA SWPC Kp forecast with your geomagnetic latitude (IGRF-14 dipole), the darkness of each 3-hour period and the MET Norway cloud forecast into chance bands per period and night, and tells you which Kp you need for aurora overhead, on the horizon or on camera.

  • Geomagnetic latitude: centred dipole from the IGRF-14 degree-1 coefficients (epoch 2025.0 plus secular variation); the north pole is computed at 80.85° N, 72.76° W for 2025.0 as published.
  • Oval boundary near magnetic midnight: 67.29° − 1.893° × Kp (mean of the 23–01 MLT fits of Carbary 2005).
  • Chance bands from your latitude minus the boundary: at or poleward of it high (aurora overhead possible), up to 4° equatorward moderate (low on the poleward horizon), up to 8° low (faint, camera only), further very low.
  • Each 3-hour period counts as dark when the Sun is 12° or more below the horizon for at least half of it; 50 % cloud lowers the band by one step, 80 % by two.

Aurora forecasts are probabilistic: Kp forecasts for more than a day ahead are often off by 1–2, substorms come and go within minutes, and the dipole latitude can differ from the corrected geomagnetic latitude by a few degrees. Treat the bands as chances, not promises.

Sources

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How to use the Skyfold Aurora Outlook

Check your chance of seeing the northern or southern lights for the next three nights from the NOAA Kp forecast, darkness and clouds.

What it is for

The Kp index is the number everyone quotes when a geomagnetic storm is coming, but whether a Kp of 5 brings aurora to your sky depends on where you live, whether it is dark at the time and whether clouds are in the way. This tool puts those pieces together.

It fetches the current NOAA Space Weather Prediction Center Kp forecast (cached for 30 minutes), computes your geomagnetic latitude from the IGRF-14 magnetic field model, checks the darkness of every three-hour period and, if you like, adds the MET Norway cloud forecast for your place. The answer is a chance band per period and per night, plus the Kp you would need for aurora overhead, on the horizon or only on camera. It cannot promise anything: aurora can flare up or fade within minutes.

Worked example

Edinburgh (55.9533, −3.1883, 50 m, Europe/London) with the NOAA forecast of 8 November 2026 pasted into the form and clouds left out.

Your place shows a geomagnetic latitude of 57.9°. To see aurora overhead you need about Kp 4.9, on the horizon about Kp 2.8, and a faint glow may show on camera from Kp 0.7. The highest Kp in the forecast is 5.

The Nights table rates the night of 7 November high: the period 00:00–03:00 on the 8th has Kp 5, which pushes the edge of the auroral oval to 57.8° — just across Edinburgh. The nights of 8 and 9 November are moderate (Kp 4.67 and 3.67 in their best periods), the night of 10 November low.

In the Three-hour periods table every daytime period reads not dark, whatever the Kp: 2026-11-08 09:00–12:00 has Kp 3.33 and a moderate geomagnetic chance, but the Sun is up.

How to read the result

  • Geomagnetic latitude is your distance from the magnetic pole, which matters more than your normal latitude: Edinburgh is magnetically further north than Moscow.
  • Oval edge is the latitude the aurora reaches near local magnetic midnight for that Kp. If your latitude is at or beyond it, the chance is high; within 4° it is moderate (low on the horizon towards the pole); within 8° low (a glow, mostly on camera); beyond that very low.
  • Your view lowers that band when the sky is not dark (the Sun less than 12° down) or when clouds cover half the sky or more.
  • Kind tells you whether a Kp value was observed, estimated or forecast.

Tips and common mistakes

  • Forecasts beyond the first night are rough: Kp predictions two or three days ahead are often off by one or two steps. Check again in the evening.
  • Get away from street lights and look towards the pole over a low horizon; the strongest displays are often around local midnight.
  • A phone camera on a long exposure picks up aurora that looks like grey cloud to the eye.
  • The dipole latitude used here can differ from the corrected geomagnetic latitude by a few degrees; treat the bands as chances.
  • With the live forecast, turn on the cloud forecast: a high band under 90 % cloud becomes very low.

FAQ

Why does the result say "not dark" during a storm?

The period falls in daylight or twilight at your place. Aurora is there, but too faint to see against a bright sky.

Does it work in the southern hemisphere?

Yes. It uses the absolute geomagnetic latitude, so Tasmania, New Zealand and Patagonia get their aurora australis chances.

Where does the data come from?

NOAA SWPC for the Kp forecast (US public domain), IGRF-14 for the magnetic field and MET Norway for clouds. The NOAA and MET requests go through the usefulweb.site server and are cached.

Can I use an older forecast?

Yes. Choose "Pasted below" and paste a NOAA 3-day forecast text or the Kp forecast JSON; the result is then only as current as that forecast.

Guide last updated:

For scripts and AI agents

  • JSON API: POST https://skyfoldauroraoutlook.usefulweb.site/api/v1/calculate (same calculation as this page)
  • Interface description: OpenAPI 3.1 · AI guide: llms.txt
  • MCP server (Streamable HTTP): https://skyfoldauroraoutlook.usefulweb.site/mcp · tool name skyfold_aurora_outlook
Example request
curl -s -X POST https://skyfoldauroraoutlook.usefulweb.site/api/v1/calculate \
  -H 'content-type: application/json' \
  -d '{…see OpenAPI examples…}'
Feedback · ideas & bug reports welcome