Checking the live aurora model…
The aurora follows Earth's magnetic field, not the map grid. Tønsberg sits at 59.1° geomagnetic latitude, and NOAA's table says the aurora reaches that line at Kp 4.
| Kp index | Reaches down to | How often |
|---|---|---|
| Kp 1 | 64.5° geomagnetic | quiet to unsettled conditions |
| Kp 2 | 62.4° geomagnetic | quiet to unsettled conditions |
| Kp 3 | 60.4° geomagnetic | quiet to unsettled conditions |
| Kp 4 | 58.3° geomagnetic | quiet to unsettled conditions |
| Kp 5 | 56.3° geomagnetic | G1 · ~900 days per 11-year solar cycle |
| Kp 6 | 54.2° geomagnetic | G2 · ~360 days per 11-year solar cycle |
| Kp 7 | 52.2° geomagnetic | G3 · ~130 days per 11-year solar cycle |
Storm frequencies are NOAA's published figures for the G-scale, averaged over an 11-year solar cycle.
Even when the Kp is high enough, street lighting can hide a low, faint aurora. Our light pollution map starts on Tønsberg and finds the darkest spots within driving distance:
Yes, but only during a geomagnetic storm. Tønsberg sits at 59.1° geomagnetic latitude, so the aurora reaches it at a Kp index of 4. The live Kp index and the three-day forecast are at the top of this page.
The aurora follows Earth's magnetic field, and the magnetic pole is not at the geographic pole — it sits near 80.7°N, 72.7°W. That is why Tønsberg at 59.3° on the map behaves like 59.1° for the aurora. It also means places at the same map latitude can need very different Kp values: northern Europe sees the aurora far more easily than the same latitude in Siberia.
Activity usually peaks around local magnetic midnight, roughly 22:00–02:00, but a substorm can start any time it is dark. At this latitude the aurora normally appears low on the northern horizon, so you need a clear view north and as little light as possible.
Yes. A bright moon washes out a faint aurora the same way city lights do. The moon tile above shows tonight's phase and illumination — under 25% is a good dark sky, over 65% will hide anything but a strong display.
The Kp index, the three-day forecast and the OVATION aurora model come from the NOAA Space Weather Prediction Center — U.S. government works in the public domain, refreshed here every 30 minutes. The Kp threshold for Tønsberg is calculated from its geomagnetic latitude using NOAA's published table. Cloud cover is not part of this page — check your local weather forecast too.