Tromsdalen · May 2027
Northern lights in Tromsdalen in May 2027
Answer
May against the rest of the year
May cloud at Tromsdalen averages 80% in NASA POWER's 2001 to 2020 record, 2 points clearer than its yearly mean. July is Tromsdalen's clearest month at 79%. By civil night times clear sky, May scores 0.0 hours at Tromsdalen, 10th of 12. Tromsø, 2 km away, averages the same 80%.
The sun never gets 6 degrees below the horizon at Tromsdalen in May 2027, so every night is twilight or daylight. June 15 is still without civil night at Tromsdalen.
May night by night
The moon runs its cycle as usual, new on May 6 and full on May 20, but with no civil night it makes no difference at Tromsdalen in May.
- 1
22% lit
no night
- 2
14% lit
no night
- 3
8% lit
no night
- 4
3% lit
no night
- 5
1% lit
no night
- 6
0% lit
no night
- 7
3% lit
no night
- 8
8% lit
no night
- 9
16% lit
no night
- 10
25% lit
no night
- 11
36% lit
no night
- 12
47% lit
no night
- 13
58% lit
no night
- 14
69% lit
no night
- 15
79% lit
no night
- 16
87% lit
no night
- 17
93% lit
no night
- 18
97% lit
no night
- 19
100% lit
no night
- 20
100% lit
no night
- 21
98% lit
no night
- 22
94% lit
no night
- 23
89% lit
no night
- 24
82% lit
no night
- 25
74% lit
no night
- 26
66% lit
no night
- 27
57% lit
no night
- 28
47% lit
no night
- 29
37% lit
no night
- 30
28% lit
no night
- 31
19% lit
no night
Each cell is the night that starts on that date. Hours are civil-dark time with the moon below the horizon; the green rule scales with them. Green outline: new moon. Bone outline: full moon.
Activity in past Mays
Quiet activity already puts the oval edge over Tromsdalen, so storm days matter more: 97 of the 930 May days from 1996 to 2025 (10%) reached Kp 5, 6th of 12 months. Tromsdalen sits at 67.5 degrees geomagnetic, inside SWPC's 60 to 75 degree band, where aurora can be seen on more than half of all nights. No storm is needed: by SWPC's rule the average oval edge is overhead at Kp 0.
May across Norway
Tromsdalen ranks 16th in Norway for civil night on May 15, behind Kristiansand at 5.1 hours. Coming from April (4.8 hours at Tromsdalen), May loses darkness, and June holds about the same.
| Town | Civil night | Cloud |
|---|---|---|
| Kristiansand | 5.1 h | 69% |
| Stavanger | 4.8 h | 71% |
| Haugesund | 4.7 h | 70% |
| Oslo | 4.5 h | 68% |
| Drammen | 4.5 h | 68% |
| Bergen | 4.3 h | 71% |
| Hamar | 4.1 h | 70% |
| Gjøvik | 4.1 h | 70% |
| Lillehammer | 3.9 h | 75% |
| Ålesund | 3.1 h | 82% |
| Molde | 2.9 h | 82% |
| Kristiansund | 2.6 h | 74% |
| Tromsdalen | 0.0 h | 80% |
Darkness and moon, every night
| Night | Civil | Astronomical | Moon-free dark | Moon-free, 10 PM to 2 AM | Moon lit |
|---|---|---|---|---|---|
| Sat May 1 | 0 min | 0 min | 0 min | 0 min | 22% |
| Sun May 2 | 0 min | 0 min | 0 min | 0 min | 14% |
| Mon May 3 | 0 min | 0 min | 0 min | 0 min | 8% |
| Tue May 4 | 0 min | 0 min | 0 min | 0 min | 3% |
| Wed May 5 | 0 min | 0 min | 0 min | 0 min | 1% |
| Thu May 6 | 0 min | 0 min | 0 min | 0 min | 0% |
| Fri May 7 | 0 min | 0 min | 0 min | 0 min | 3% |
| Sat May 8 | 0 min | 0 min | 0 min | 0 min | 8% |
| Sun May 9 | 0 min | 0 min | 0 min | 0 min | 16% |
| Mon May 10 | 0 min | 0 min | 0 min | 0 min | 25% |
| Tue May 11 | 0 min | 0 min | 0 min | 0 min | 36% |
| Wed May 12 | 0 min | 0 min | 0 min | 0 min | 47% |
| Thu May 13 | 0 min | 0 min | 0 min | 0 min | 58% |
| Fri May 14 | 0 min | 0 min | 0 min | 0 min | 69% |
| Sat May 15 | 0 min | 0 min | 0 min | 0 min | 79% |
| Sun May 16 | 0 min | 0 min | 0 min | 0 min | 87% |
| Mon May 17 | 0 min | 0 min | 0 min | 0 min | 93% |
| Tue May 18 | 0 min | 0 min | 0 min | 0 min | 97% |
| Wed May 19 | 0 min | 0 min | 0 min | 0 min | 100% |
| Thu May 20 | 0 min | 0 min | 0 min | 0 min | 100% |
| Fri May 21 | 0 min | 0 min | 0 min | 0 min | 98% |
| Sat May 22 | 0 min | 0 min | 0 min | 0 min | 94% |
| Sun May 23 | 0 min | 0 min | 0 min | 0 min | 89% |
| Mon May 24 | 0 min | 0 min | 0 min | 0 min | 82% |
| Tue May 25 | 0 min | 0 min | 0 min | 0 min | 74% |
| Wed May 26 | 0 min | 0 min | 0 min | 0 min | 66% |
| Thu May 27 | 0 min | 0 min | 0 min | 0 min | 57% |
| Fri May 28 | 0 min | 0 min | 0 min | 0 min | 47% |
| Sat May 29 | 0 min | 0 min | 0 min | 0 min | 37% |
| Sun May 30 | 0 min | 0 min | 0 min | 0 min | 28% |
| Mon May 31 | 0 min | 0 min | 0 min | 0 min | 19% |
Questions
- Can you see the northern lights in Tromsdalen in May?
- Not in May 2027. The sun stays above -6 degrees every night at Tromsdalen, so there is no civil darkness.
- How dark is Tromsdalen in May?
- Tromsdalen averages 0.0 hours of civil night a night in May 2027, from 0 min on the 1st to 0 min on the last night.
- How cloudy is Tromsdalen in May?
- NASA POWER's 2001 to 2020 climatology gives Tromsdalen's 1 degree cell 80% mean cloud in May, against 82% for the whole year. It is an all-hours average, not a forecast.
- What is the best night in May 2027 for aurora in Tromsdalen?
- No night in May 2027 has moon-free darkness inside 10 PM to 2 AM at Tromsdalen.
- Is May or June better in Tromsdalen?
- By civil night times the clear share, May scores 0.0 hours at Tromsdalen and June 0.0. They are level.
Sources and verification
- SunCalchttps://github.com/mourner/suncalc
- NASA POWER climatologyhttps://power.larc.nasa.gov/docs/services/api/temporal/climatology/
- GFZ Potsdam Kp indexhttps://kp.gfz.de/en/data
- 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.