NOAA data, checked 12:21 UTC
Kp index now
Latest 3-hour Kp: 1.33, Quiet. NOAA storm level: G0 (none). The minute-by-minute estimate is Kp 0.
The minute value is an early estimate and jumps around; the official Kp is set for each 3-hour block and checked again later.
Kp forecast for the next 3 days
Observed Kp for the last two days and NOAA's forecast for each 3-hour block. Kp 5 and above is a geomagnetic storm.
The Kp scale in plain words
Kp is a 0–9 score for how strongly the Earth's magnetic field is being shaken by the solar wind. The higher it goes, the further from the poles the northern lights reach. Kp 0–2 is a quiet night; Kp 5 and above is a geomagnetic storm.
- Kp 0–2 Quiet Only under the auroral oval: northern Norway, Swedish and Finnish Lapland, Iceland, Alaska, northern Canada.
- Kp 3 Unsettled next 24 h Bright in the Arctic; low on the horizon in central Scandinavia and southern Iceland.
- Kp 4 Active Overhead in the Arctic; low in the north from southern Norway, Sweden, Finland and northern Scotland.
- Kp 5 Minor storm (G1) Scotland, southern Scandinavia, the Baltic states, the northern US states and southern Canada.
- Kp 6 Moderate storm (G2) Northern England, Denmark, northern Germany and Poland, the US Midwest — often clearer in photos than to the eye.
- Kp 7 Strong storm (G3) Most of the UK, the Netherlands, Germany, Poland, Czechia; red glow in photos from France and the northern Alps.
- Kp 8 Severe storm (G4) Central Europe to the eye; red sky in photos from northern Italy, Spain, the Balkans and Turkey's Black Sea coast.
- Kp 9 Extreme storm (G5) Seen across Europe and the US; in photos as far south as the Mediterranean, Turkey and North Africa (May 2024).
Kp needed by country
For each country: the easiest town in our list and the Kp at which the aurora can be seen there by eye on a clear, dark night. Cameras pick it up at a lower Kp.
What is the Kp index?
Kp is a number from 0 to 9 that shows how much the Earth's magnetic field is being disturbed by the solar wind. A higher Kp means a bigger, brighter aurora oval that reaches further from the poles. Kp 0–2 is quiet, Kp 4 is active and Kp 5 or more is a geomagnetic storm (G1 to G5 on NOAA's scale).
How is Kp measured?
Kp comes from 13 magnetometer stations at mid latitudes around the world. Each one measures how much the magnetic field swings during a 3-hour block (00–03 UTC, 03–06 UTC and so on). The results are combined into one planetary value. The scale is quasi-logarithmic: each step means a much stronger disturbance than the one before. It is given in thirds, such as 4-, 4 and 4+ (written here as 3.67, 4.00 and 4.33).
Kp, Hp30 and real-time estimates
The official Kp from GFZ Potsdam is only final after the 3-hour block ends, and it is checked again later. To show what is happening now, NOAA estimates Kp every minute from fewer stations. GFZ also publishes Hp30, a similar index for 30-minute blocks that is not capped at 9. Real-time values can be revised, so treat them as a guide.
Why Kp alone is not enough
Kp tells you how strong the activity is around the whole planet, not what you will see from your garden. The direction of the solar wind's magnetic field (Bz) matters a lot: when it points south for a while, the aurora can flare up within minutes even if Kp is low. You also need a dark sky after twilight, a view to the north (or south in the southern hemisphere) and few clouds.
Questions about the Kp index
What Kp do I need to see the northern lights?
It depends on where you are. Under the auroral oval (northern Norway, Lapland, Iceland, Alaska) Kp 1–3 is often enough. Southern Scandinavia and Scotland usually need Kp 5, central Europe and the northern United States Kp 6–7, and southern Europe Kp 8–9.
How often is the Kp index updated?
The official Kp is given for each 3-hour block. NOAA also publishes an estimate every minute, which this page shows. Our page checks NOAA's data every minute for the estimate and every 15 minutes for the 3-hour values and the forecast.
How accurate is the Kp forecast?
The next few hours are fairly reliable, because the solar wind is measured about an hour before it reaches Earth. Forecasts for 1–3 days ahead are based on what is seen on the Sun and can be off by several Kp points, especially for the timing of storms.
Is a high Kp dangerous?
Not for people on the ground. Strong storms can disturb power grids, satellites, GPS and radio, but they do not harm your health. For aurora watchers a high Kp is simply good news.
Keep watching
Data: NOAA SWPC (public domain): planetary K index, 1-minute estimated Kp and the 3-day forecast. Official Kp: GFZ Potsdam.