Aurora forecast and Kp index for tonight, for your location
This aurora forecast fetches the planetary Kp index and its 3-day forecast from NOAA’s Space Weather Prediction Center, then tells you what it means where you are. Press Get live Kp forecast to see the current Kp, the NOAA geomagnetic storm level (G1–G5), and for every 3-hour window whether your sky is dark and whether aurora could be overhead, low on the horizon or out of reach.
Even without live data, the table at the bottom shows the Kp you need for your own city: the page converts your latitude and longitude into magnetic latitude, which is what controls the auroral oval. Pick a city, type coordinates or use your location — the location never leaves your browser.
How to use the Aurora Forecast & Kp Index
- Choose your City or type Latitude and Longitude (or press Use my location), and set your time zone.
- Read the note under the result: your magnetic latitude and the Kp needed for aurora on your horizon and overhead.
- Press Get live Kp forecast for the current Kp, storm level and the best dark-sky window in the next three days.
- Scan the chart and the table: each 3-hour block shows Kp, NOAA G-scale, whether it was observed, estimated or predicted, how dark your sky is, and the outlook where you are.
- Tick Load live data automatically if you want the forecast fetched every time you open this page on this device.
Aurora Forecast & Kp Index features
Live NOAA data
The official planetary K-index forecast and 1-minute estimated Kp from SWPC, fetched straight from NOAA only when you ask.
Your magnetic latitude
Converted with the AACGM-v2 model, which accounts for the tilted, offset magnetic field — London is at about 47° magnetic latitude, not 51°.
Darkness check
Each forecast window is matched against the Sun’s position for your location, so a strong storm in daylight is not counted.
Clear verdicts
Overhead possible, low on the horizon, or unlikely — for the current Kp, each forecast block and each Kp level from 0 to 9.
Graceful offline
Clear messages if NOAA cannot be reached; the location table needs no network.
Kp, the G-scale and where aurora can be seen
Kp runs from 0 (quiet) to 9 (extreme) in thirds — 5−, 5, 5+ — and is measured over 3-hour blocks. SWPC’s rule of thumb is that the equatorward edge of the auroral oval sits near 66° magnetic latitude at Kp 0 and moves about 2° towards the equator for each Kp step, reaching about 48° at Kp 9. Those are averages: SWPC itself calls the relation approximate.
You do not need the aurora overhead to see it. Its lower edge is about 100 km up, so from 600–700 km further away it can still appear 5° above your poleward horizon; this page uses that geometry (about 6.2° of latitude) for “low on the horizon”. Cameras pick up faint aurora the eye misses, so photographers often succeed a little further out.
| Kp | NOAA level | Oval edge (magnetic lat.) | SWPC: typically seen as far as |
|---|---|---|---|
| 0–4 | Below storm level | 66°–58° | Not part of the G-scale |
| 5 | G1 minor | 56° | Northern Michigan and Maine |
| 6 | G2 moderate | 54° | New York and Idaho (≈ 55°) |
| 7 | G3 strong | 52° | Illinois and Oregon (≈ 50°) |
| 8, 9− | G4 severe | 50° | Alabama and northern California (≈ 45°) |
| 9 | G5 extreme | 48° | Florida and southern Texas (≈ 40°) |
How to use the forecast
Look for a dark, clear night with Kp at or above your horizon value, ideally away from city lights and with an open view towards the pole: north in the northern hemisphere, south in the southern. The moon phase calculator tells you whether moonlight will wash out faint displays, and the sun position calculator gives exact twilight times.
Forecasts beyond 24 hours are uncertain: the Kp values for the coming days come from SWPC’s forecasters and depend on solar-wind conditions that spacecraft can measure only 30–60 minutes before they reach Earth. Treat predicted values as a reason to keep watching, not a promise.
Data and sources
Kp data: NOAA SWPC, services.swpc.noaa.gov (planetary K-index forecast and 1-minute estimated Kp), US-government information in the public domain; this page is not affiliated with or endorsed by NOAA. Kp-to-latitude rule: SWPC “Tips on viewing the aurora”; G-scale thresholds and “seen as far as” examples: NOAA Space Weather Scales. Magnetic latitude: AACGM-v2 (Shepherd 2014), epoch 2026.5, at ground level; geographic latitude below 20° is treated as outside the auroral zones.
Aurora Forecast & Kp Index FAQ
What is the Kp index today?
Press Get live Kp forecast. The large number is the latest Kp: the 1-minute estimate when available, otherwise the current 3-hour value from NOAA SWPC.
What Kp do I need to see the northern lights?
It depends on your magnetic latitude. The page states it for your location: for example, about Kp 3.5 in Edinburgh and Kp 6.3 in London for aurora low on the northern horizon.
Can I see the aurora tonight from my location?
Check the forecast table: a window marked “Overhead possible” or “Low on the horizon” with a dark sky is your chance, weather permitting.
What do G1 to G5 mean?
NOAA’s geomagnetic storm scale: G1 minor (Kp 5), G2 moderate (Kp 6), G3 strong (Kp 7), G4 severe (Kp 8 or 9−) and G5 extreme (Kp 9).
Does it work for the southern lights?
Yes. Southern locations get a negative magnetic latitude, and the advice switches to the southern horizon.
Why does my magnetic latitude differ from my latitude?
The magnetic poles are offset from the geographic poles and the field is not a perfect dipole, so Western Europe sits several degrees further from the auroral zone than North America at the same latitude.