Can you see the northern lights in Vallentuna in December?

On dark, clear nights with enough activity. 31 of 31 nights at Vallentuna have civil darkness, and 19% of past December days reached Kp 4.

How dark is Vallentuna in December?

Vallentuna averages 15.8 hours of civil night a night in December 2026, from 15 h 31 min on the 1st to 15 h 50 min on the last night.

How cloudy is Vallentuna in December?

NASA POWER's 2001 to 2020 climatology gives Vallentuna's 1 degree cell 88% mean cloud in December, against 75% for the whole year. It is an all-hours average, not a forecast.

What is the best night in December 2026 for aurora in Vallentuna?

By darkness and moon alone, Dec 3, with 4 h of moon-free darkness inside 10 PM to 2 AM at Vallentuna. Activity on that date will only be known hours ahead.

Is December or January better in Vallentuna?

By civil night times the clear share, December scores 1.9 hours at Vallentuna and January 1.7. December comes out ahead.

Vallentuna · December 2026

Northern lights in Vallentuna in December 2026

Answer

December gives Vallentuna 15.9 hours of civil night on the 15th, the darkest month of its year, under 88% mean cloud. 19% of December days since 1996 reached Kp 4, enough for the oval edge to reach Vallentuna.

15.8 h

civil night, average night

SunCalc for 59.53, 18.08; NASA POWER; GFZ Kp

December against the rest of the year

1.7

1.8

2.4

1.7

0.6

1.3

2.1

2.7

2.3

1.9

December cloud at Vallentuna averages 88% in NASA POWER's 2001 to 2020 record, 13 points cloudier than its yearly mean. May is Vallentuna's clearest month at 62%. By civil night times clear sky, December scores 1.9 hours at Vallentuna, 7th of 12. Sollentuna, 14 km away, averages 83%, clearer by 5 points.

Civil night at Vallentuna starts December at 15 h 31 min and reaches 15 h 50 min by December 31 as the nights lengthen by 0.3 hours. SWPC's 10 PM to 2 AM window is fully dark on every night. True astronomical darkness, the sun 18 degrees down, lasts 12.4 hours on the 15th.

December night by night

December opens toward a new moon on Dec 9, with full moon on Dec 24, in Europe/Stockholm dates. Vallentuna gets 265 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 3 (4 h), Dec 4 (4 h), Dec 5 (4 h).

1
43% lit
8.2 h
2
32% lit
9.7 h
3
23% lit
11.2 h
4
15% lit
12.7 h
5
9% lit
14.2 h
6
4% lit
15.7 h
7
1% lit
15.7 h
8
0% lit
15.8 h
9
1% lit
15.8 h
New
10
3% lit
15.8 h
11
8% lit
15.5 h
12
13% lit
14.0 h
13
20% lit
12.6 h
14
28% lit
11.2 h
15
37% lit
9.8 h
16
47% lit
8.4 h
17
58% lit
7.0 h
18
68% lit
5.4 h
19
78% lit
3.8 h
20
86% lit
2.0 h
21
93% lit
0.3 h
22
98% lit
0.0 h
23
100% lit
0.0 h
24
99% lit
0.0 h
Full
25
95% lit
0.6 h
26
88% lit
2.5 h
27
79% lit
4.3 h
28
69% lit
5.9 h
29
59% lit
7.4 h
30
48% lit
8.9 h
31
38% lit
10.4 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

Vallentuna needs Kp 4 for the average oval edge to sit overhead. 173 of the 930 December days from 1996 to 2025 (19%) reached it in the GFZ Potsdam record, one of the three quietest months for that level; storm days with Kp 5 or more made up 5%. Vallentuna sits at 58.2 degrees geomagnetic. By SWPC's rule the average oval edge is overhead at Kp 4, and aurora is usually visible on the northern horizon at G1 (Kp 5) or less.

December across Sweden

Vallentuna ranks 13th in Sweden for civil night on December 15, behind Kiruna at 18.3 hours. Coming from November (14.7 hours at Vallentuna), December adds darkness, and January brings shorter nights (15.3 hours on the 15th). The December solstice falls on December 21, 21:49 Vallentuna time.

Civil night on December 15 and December cloud, month-page towns in Sweden
Town	Civil night	Cloud
Kiruna	18.3 h	80%
Boden	17.5 h	75%
Luleå	17.4 h	80%
Piteå	17.3 h	75%
Skellefteå	17.2 h	76%
Umeå	16.9 h	80%
Örnsköldsvik	16.8 h	73%
Östersund	16.7 h	75%
Härnösand	16.6 h	73%
Sundsvall	16.5 h	73%
Hudiksvall	16.4 h	74%
Uppsala	16.0 h	83%
Vallentuna	15.9 h	88%

Darkness and moon, every night

Vallentuna, December 2026: each night from local noon to the next noon
Night	Civil	Astronomical	Moon-free dark	Moon-free, 10 PM to 2 AM	Moon lit
Tue Dec 1	15 h 31 min	12 h 5 min	8 h 13 min	2 h 5 min	43%
Wed Dec 2	15 h 33 min	12 h 7 min	9 h 43 min	3 h 34 min	32%
Thu Dec 3	15 h 36 min	12 h 9 min	11 h 12 min	4 h	23%
Fri Dec 4	15 h 38 min	12 h 10 min	12 h 43 min	4 h	15%
Sat Dec 5	15 h 40 min	12 h 12 min	14 h 14 min	4 h	9%
Sun Dec 6	15 h 42 min	12 h 14 min	15 h 42 min	4 h	4%
Mon Dec 7	15 h 44 min	12 h 15 min	15 h 44 min	4 h	1%
Tue Dec 8	15 h 46 min	12 h 17 min	15 h 46 min	4 h	0%
Wed Dec 9	15 h 48 min	12 h 18 min	15 h 48 min	4 h	1%
Thu Dec 10	15 h 49 min	12 h 19 min	15 h 49 min	4 h	3%
Fri Dec 11	15 h 51 min	12 h 20 min	15 h 29 min	4 h	8%
Sat Dec 12	15 h 52 min	12 h 21 min	14 h 2 min	4 h	13%
Sun Dec 13	15 h 53 min	12 h 22 min	12 h 35 min	4 h	20%
Mon Dec 14	15 h 54 min	12 h 23 min	11 h 10 min	4 h	28%
Tue Dec 15	15 h 55 min	12 h 24 min	9 h 46 min	4 h	37%
Wed Dec 16	15 h 56 min	12 h 24 min	8 h 23 min	2 h 41 min	47%
Thu Dec 17	15 h 56 min	12 h 25 min	6 h 57 min	1 h 15 min	58%
Fri Dec 18	15 h 57 min	12 h 25 min	5 h 26 min	0 min	68%
Sat Dec 19	15 h 57 min	12 h 25 min	3 h 48 min	0 min	78%
Sun Dec 20	15 h 57 min	12 h 26 min	2 h 3 min	0 min	86%
Mon Dec 21	15 h 57 min	12 h 26 min	16 min	0 min	93%
Tue Dec 22	15 h 57 min	12 h 26 min	0 min	0 min	98%
Wed Dec 23	15 h 57 min	12 h 25 min	0 min	0 min	100%
Thu Dec 24	15 h 57 min	12 h 25 min	0 min	0 min	99%
Fri Dec 25	15 h 56 min	12 h 25 min	38 min	0 min	95%
Sat Dec 26	15 h 56 min	12 h 24 min	2 h 30 min	0 min	88%
Sun Dec 27	15 h 55 min	12 h 24 min	4 h 15 min	0 min	79%
Mon Dec 28	15 h 54 min	12 h 23 min	5 h 52 min	0 min	69%
Tue Dec 29	15 h 53 min	12 h 22 min	7 h 24 min	1 h 17 min	59%
Wed Dec 30	15 h 52 min	12 h 21 min	8 h 53 min	2 h 48 min	48%
Thu Dec 31	15 h 50 min	12 h 20 min	10 h 22 min	4 h	38%

Moon lit: SunCalc illuminated fraction at the middle of the 10 PM to 2 AM window.

Questions

Can you see the northern lights in Vallentuna in December?: On dark, clear nights with enough activity. 31 of 31 nights at Vallentuna have civil darkness, and 19% of past December days reached Kp 4.
How dark is Vallentuna in December?: Vallentuna averages 15.8 hours of civil night a night in December 2026, from 15 h 31 min on the 1st to 15 h 50 min on the last night.
How cloudy is Vallentuna in December?: NASA POWER's 2001 to 2020 climatology gives Vallentuna's 1 degree cell 88% mean cloud in December, against 75% for the whole year. It is an all-hours average, not a forecast.
What is the best night in December 2026 for aurora in Vallentuna?: By darkness and moon alone, Dec 3, with 4 h of moon-free darkness inside 10 PM to 2 AM at Vallentuna. Activity on that date will only be known hours ahead.
Is December or January better in Vallentuna?: By civil night times the clear share, December scores 1.9 hours at Vallentuna and January 1.7. December comes out ahead.

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.