Comparison
Helsinki vs Tallinn for the northern lights
Answer
Side by side
| Figure | Helsinki | Tallinn |
|---|---|---|
| Dipole latitude | 57.7° | 57.1° |
| Kp for the oval edge overhead | Kp 5 | Kp 5 |
| Civil night, December 15 | 16.0 h | 15.9 h |
| Dark-season days | 299 | 305 |
| Nights with no civil darkness | 10 | 0 |
| Dark-month cloud, NASA POWER | 74% | 75% |
| Solar midnight, December 15 | 00:15 | 00:16 |
Helsinki sits at 57.7 degrees geomagnetic. By SWPC's rule the average oval edge is overhead at Kp 5, and aurora is usually visible on the northern horizon at G1 (Kp 5) or less. Tallinn sits at 57.1 degrees geomagnetic. By SWPC's rule the average oval edge is overhead at Kp 5, and aurora is usually visible on the northern horizon at G1 (Kp 5) or less.
Civil night month by month
On December 15 Helsinki has 16.0 hours of civil night and Tallinn 15.9. Across the 15th of each month, Helsinki is darker in 4 months and Tallinn in 6. The widest gap comes in June, when Tallinn has 1.6 more hours.
| Month | Helsinki | Tallinn | Difference |
|---|---|---|---|
| January | 15.4 h | 15.3 h | +0.1 h |
| February | 13.2 h | 13.1 h | +0.1 h |
| March | 10.7 h | 10.7 h | +0.0 h |
| April | 7.7 h | 7.8 h | -0.1 h |
| May | 4.4 h | 4.7 h | -0.3 h |
| June | 0.2 h | 1.8 h | -1.6 h |
| July | 2.9 h | 3.4 h | -0.5 h |
| August | 6.5 h | 6.7 h | -0.2 h |
| September | 9.6 h | 9.7 h | -0.1 h |
| October | 12.3 h | 12.3 h | +0.0 h |
| November | 14.7 h | 14.6 h | +0.1 h |
| December | 16.0 h | 15.9 h | +0.1 h |
Season and midnight sun
Helsinki has no civil darkness from June 16 to June 25, 10 nights in 2026, and its dark season, 4 or more evening hours of civil night, lasts 299 days. Tallinn has some civil darkness every night of 2026, and its dark season, 4 or more evening hours of civil night, lasts 305 days.
Distance, cloud and time zones
The two towns are 82 km apart by great circle. In the dark months both average about 74% cloud in NASA POWER's 2001 to 2020 record. Helsinki's best month by civil night times clear sky is March. Tallinn's best month by civil night times clear sky is March. Time zones: Europe/Helsinki and Europe/Tallinn.
For tonight, open the live pages for Helsinki and Tallinn, which carry the live OVATION cell.
Questions
- Is Helsinki or Tallinn better for the northern lights?
- Helsinki sits closer to the oval, at 57.7 degrees geomagnetic against 57.1. Darkness, cloud and your dates decide the rest; the tables on this page show both towns month by month.
- Which has longer nights in December, Helsinki or Tallinn?
- Helsinki, with 16.0 hours of civil night on December 15 against 15.9 in Tallinn.
- What Kp do Helsinki and Tallinn need?
- By SWPC's rule of 66 degrees at Kp 0 and 2 degrees per step, Helsinki needs about Kp 5 and Tallinn Kp 5 for the average oval edge to sit overhead.
- When is it too light for aurora in Helsinki and Tallinn?
- Helsinki: June 16 to June 25. Tallinn: never, every night has civil darkness.
- Which is clearer, Helsinki or Tallinn?
- Helsinki, with 74% mean cloud in the months with 4 hours or more of civil night against 75% in Tallinn (NASA POWER, 2001 to 2020).
Sources and verification
- IGRF-14 coefficients, NOAA NCEIhttps://www.ngdc.noaa.gov/IAGA/vmod/coeffs/igrf14coeffs.txt
- SunCalchttps://github.com/mourner/suncalc
- GeoNameshttps://www.geonames.org/export/
- NASA POWER climatologyhttps://power.larc.nasa.gov/docs/services/api/temporal/climatology/
- NOAA SWPC, Tips on viewing the aurorahttps://www.spaceweather.gov/content/tips-viewing-aurora
Quoted figures last checked against their sources on 2026-09-30; next review 2026-12-31. Computed figures come from SunCalc and the IGRF-14 dipole as described in the methodology. Every quote is listed in the sources ledger.