Aurora Forecast
Check the current Kp index and NOAA's 3-day geomagnetic forecast, then see what it means where you are: the Kp needed to see the aurora from your latitude, whether it will be dark, and where the auroral oval sits on the map right now.
Last updated:
Aurora oval map
3-day Kp forecast (NOAA SWPC)
How to use the Aurora Forecast
- Choose your location from the list, press Use my location, or enter coordinates.
- Read the summary: it compares tonight's forecast Kp with the Kp needed at your latitude and checks that it will be dark.
- Look at the map to see the live aurora oval from NOAA's OVATION model; green to red means rising probability.
- Check the 3-day chart for upcoming storms; bars above the green dashed line are strong enough for your location.
- Drag the Kp slider to see how far the oval reaches during stronger storms, then press Check latest forecast later for fresh data.
How the aurora chances are worked out
The aurora appears in an oval-shaped band around each geomagnetic pole. When the solar wind disturbs Earth's magnetic field, the planetary Kp index rises and the oval widens toward the equator. This page combines three things:
- Your geomagnetic latitude, from a centered dipole with its north pole at 80.8° N, 72.7° W (IGRF, 2025): sin Φ = sin φ · sin φp + cos φ · cos φp · cos(λ − λp).
- The Kp needed: the oval's equatorward edge near local midnight is approximately 66.5° − 2.05 × Kp geomagnetic latitude. Aurora at 100–300 km altitude can be seen low on the horizon from about 6° farther equatorward, which is shown as the view line on the map.
- Darkness: the Sun must be below about −12° (nautical twilight) for all but the brightest displays, computed for your exact location.
The live map uses NOAA's OVATION Prime model, which estimates the probability of visible aurora over the next 30 to 90 minutes from solar wind data measured about 1.5 million km upstream of Earth.
Kp levels and where the aurora reaches
| Kp | NOAA scale | Oval edge (geomagnetic lat.) | Typical places with a chance (North America / Europe) |
|---|---|---|---|
| 0–2 | Quiet | about 62–66° | Fairbanks, Yellowknife, Tromsø, northern Iceland |
| 3 | Unsettled | about 60° | Anchorage, southern Iceland, northern Sweden and Finland |
| 4 | Active | about 58° | Edmonton, Oslo, Helsinki, northern Scotland |
| 5 | G1 minor | about 56° | Northern US border states, southern Scandinavia, Scotland |
| 6 | G2 moderate | about 54° | Seattle, Chicago, Ireland, Denmark |
| 7 | G3 strong | about 52° | New York, Iowa, England, northern Germany, Poland |
| 8–9 | G4–G5 severe to extreme | about 48–50° | Much of the US, central Europe, occasionally farther south |
The examples are approximate and assume a dark site looking toward the pole; strong storms often reach farther than the rule of thumb, and quiet nights can still bring surprises.
Tips for seeing the northern or southern lights
- Get away from lights and face the pole (north in the Northern Hemisphere, south in the Southern) with a low, open horizon.
- Give it time. Activity comes in waves called substorms; a quiet glow can brighten into moving curtains within minutes.
- Use a camera. A phone in night mode or a camera at 5–15 seconds exposure picks up green and red that your eyes may see as gray.
- Mind the Moon. A bright Moon makes faint aurora harder to see; check the Moonrise and Moonset Calculator for moon-free hours.
- Watch for storm alerts. Large solar eruptions take one to three days to arrive, so a G2 or stronger watch in the 3-day forecast is the best early warning.
Frequently asked questions
What is the Kp index?
Kp is a planetary index of geomagnetic activity from 0 (quiet) to 9 (extreme storm), based on magnetometer readings around the world in 3-hour blocks. Higher Kp means the auroral oval expands toward the equator, so the northern and southern lights can be seen from lower latitudes.
What Kp do I need to see the northern lights?
It depends on your geomagnetic latitude rather than your ordinary latitude. As a rule of thumb the oval's equatorward edge sits near 66.5° geomagnetic latitude at Kp 0 and moves about 2° closer to the equator per Kp step, reaching roughly 48° at Kp 9. Aurora high in the sky can be seen low on the horizon from several degrees farther away.
Why does geomagnetic latitude matter?
The aurora forms in a ring around Earth's magnetic pole, which in 2025 sits near 80.8° N, 72.7° W, over the Canadian Arctic. That is why places in North America see aurora at lower geographic latitudes than places in Europe or Asia at the same latitude.
What do G1 to G5 mean?
NOAA's geomagnetic storm scale: G1 (minor) corresponds to Kp 5, G2 (moderate) to Kp 6, G3 (strong) to Kp 7, G4 (severe) to Kp 8 and G5 (extreme) to Kp 9. Storms of G3 or more can push the aurora to mid-latitudes.
How accurate is an aurora forecast?
The 30 to 90 minute OVATION forecast is fairly reliable because it uses solar wind measured upstream of Earth. The 3-day Kp forecast depends on predicting when solar eruptions arrive and how they are oriented, so it can easily be off by several hours or a couple of Kp points.
What is the best time to see the aurora?
Usually around local magnetic midnight, roughly 10 p.m. to 2 a.m., when you face the night side of the oval. You need a clear, dark sky away from city lights; a bright Moon or twilight washes out faint displays. Phone cameras in night mode often show color before your eyes do.
Where does the data come from?
Current and forecast Kp and the OVATION aurora model are loaded straight from NOAA's Space Weather Prediction Center public data feeds when you open the page. Darkness, Moon brightness, geomagnetic latitude and the Kp-based oval are calculated in your browser.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.