Longyearbyen · December 2026
Northern lights in Longyearbyen in December 2026
Answer
December against the rest of the year
December cloud at Longyearbyen averages 74% in NASA POWER's 2001 to 2020 record, 2 points clearer than its yearly mean. April is Longyearbyen's clearest month at 67%. That makes December the best month of Longyearbyen's year by civil night times clear sky, 6.2 hours. Alta, 945 km away, averages 83%, cloudier by 9 points.
Civil night at Longyearbyen starts December at 24 h and reaches almost the same on December 31. SWPC's 10 PM to 2 AM window is fully dark on every night. True astronomical darkness, the sun 18 degrees down, lasts 14.9 hours on the 15th.
December night by night
December opens toward a new moon on Dec 9, with full moon on Dec 24, in Arctic/Longyearbyen dates. Longyearbyen gets 418 hours of civil night with the moon below the horizon across the month. The best of them for moon-free darkness inside 10 PM to 2 AM: Dec 2 (4 h), Dec 3 (4 h), Dec 4 (4 h).
- 1
43% lit
10.0 h
- 2
32% lit
15.1 h
- 3
23% lit
22.6 h
- 4
15% lit
24.0 h
- 5
9% lit
24.0 h
- 6
4% lit
24.0 h
- 7
1% lit
24.0 h
- 8
0% lit
24.0 h
- 9
1% lit
24.0 h
- 10
3% lit
24.0 h
- 11
8% lit
24.0 h
- 12
13% lit
24.0 h
- 13
20% lit
24.0 h
- 14
28% lit
24.0 h
- 15
37% lit
18.1 h
- 16
47% lit
13.1 h
- 17
58% lit
8.2 h
- 18
68% lit
0.0 h
- 19
78% lit
0.0 h
- 20
86% lit
0.0 h
- 21
93% lit
0.0 h
- 22
98% lit
0.0 h
- 23
100% lit
0.0 h
- 24
99% lit
0.0 h
- 25
95% lit
0.0 h
- 26
88% lit
0.0 h
- 27
79% lit
0.0 h
- 28
69% lit
9.4 h
- 29
59% lit
14.2 h
- 30
48% lit
19.5 h
- 31
38% lit
24.0 h
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 Decembers
Quiet activity already puts the oval edge over Longyearbyen, so storm days matter more: 44 of the 930 December days from 1996 to 2025 (5%) reached Kp 5, one of the three quietest months for that level. Longyearbyen sits at 75.3 degrees geomagnetic, poleward of SWPC's 60 to 75 degree band. The quiet oval can lie south of the town, so aurora often shows low in the southern sky, and storms push the oval farther south.
December across Svalbard and Jan Mayen
Coming from November (24.0 hours at Longyearbyen), December changes little, and January holds about the same. The December solstice falls on December 21, 21:49 Longyearbyen time.
Darkness and moon, every night
| Night | Civil | Astronomical | Moon-free dark | Moon-free, 10 PM to 2 AM | Moon lit |
|---|---|---|---|---|---|
| Tue Dec 1 | 24 h | 13 h 58 min | 10 h 1 min | 1 h 46 min | 43% |
| Wed Dec 2 | 24 h | 14 h 4 min | 15 h 4 min | 4 h | 32% |
| Thu Dec 3 | 24 h | 14 h 10 min | 22 h 33 min | 4 h | 23% |
| Fri Dec 4 | 24 h | 14 h 16 min | 24 h | 4 h | 15% |
| Sat Dec 5 | 24 h | 14 h 21 min | 24 h | 4 h | 9% |
| Sun Dec 6 | 24 h | 14 h 26 min | 24 h | 4 h | 4% |
| Mon Dec 7 | 24 h | 14 h 30 min | 24 h | 4 h | 1% |
| Tue Dec 8 | 24 h | 14 h 35 min | 24 h | 4 h | 0% |
| Wed Dec 9 | 24 h | 14 h 39 min | 24 h | 4 h | 1% |
| Thu Dec 10 | 24 h | 14 h 42 min | 24 h | 4 h | 3% |
| Fri Dec 11 | 24 h | 14 h 46 min | 24 h | 4 h | 8% |
| Sat Dec 12 | 24 h | 14 h 49 min | 24 h | 4 h | 13% |
| Sun Dec 13 | 24 h | 14 h 52 min | 24 h | 4 h | 20% |
| Mon Dec 14 | 24 h | 14 h 54 min | 24 h | 4 h | 28% |
| Tue Dec 15 | 24 h | 14 h 56 min | 18 h 9 min | 4 h | 37% |
| Wed Dec 16 | 24 h | 14 h 58 min | 13 h 8 min | 2 h 52 min | 47% |
| Thu Dec 17 | 24 h | 15 h | 8 h 10 min | 0 min | 58% |
| Fri Dec 18 | 24 h | 15 h 1 min | 0 min | 0 min | 68% |
| Sat Dec 19 | 24 h | 15 h 1 min | 0 min | 0 min | 78% |
| Sun Dec 20 | 24 h | 15 h 2 min | 0 min | 0 min | 86% |
| Mon Dec 21 | 24 h | 15 h 2 min | 0 min | 0 min | 93% |
| Tue Dec 22 | 24 h | 15 h 2 min | 0 min | 0 min | 98% |
| Wed Dec 23 | 24 h | 15 h 1 min | 0 min | 0 min | 100% |
| Thu Dec 24 | 24 h | 15 h 1 min | 0 min | 0 min | 99% |
| Fri Dec 25 | 24 h | 14 h 59 min | 0 min | 0 min | 95% |
| Sat Dec 26 | 24 h | 14 h 58 min | 0 min | 0 min | 88% |
| Sun Dec 27 | 24 h | 14 h 56 min | 0 min | 0 min | 79% |
| Mon Dec 28 | 24 h | 14 h 54 min | 9 h 23 min | 0 min | 69% |
| Tue Dec 29 | 24 h | 14 h 51 min | 14 h 13 min | 2 h 2 min | 59% |
| Wed Dec 30 | 24 h | 14 h 48 min | 19 h 32 min | 4 h | 48% |
| Thu Dec 31 | 24 h | 14 h 45 min | 24 h | 4 h | 38% |
Questions
- Can you see the northern lights in Longyearbyen in December?
- On dark, clear nights with enough activity. 31 of 31 nights at Longyearbyen have civil darkness, and 5% of past December days reached Kp 5.
- How dark is Longyearbyen in December?
- Longyearbyen averages 24.0 hours of civil night a night in December 2026, from 24 h on the 1st to 24 h on the last night.
- How cloudy is Longyearbyen in December?
- NASA POWER's 2001 to 2020 climatology gives Longyearbyen's 1 degree cell 74% mean cloud in December, against 76% for the whole year. It is an all-hours average, not a forecast.
- What is the best night in December 2026 for aurora in Longyearbyen?
- By darkness and moon alone, Dec 2, with 4 h of moon-free darkness inside 10 PM to 2 AM at Longyearbyen. Activity on that date will only be known hours ahead.
- Is December or January better in Longyearbyen?
- By civil night times the clear share, December scores 6.2 hours at Longyearbyen and January 6.2. 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.