Can you see the northern lights in Sligo in December?

On dark, clear nights with enough activity. 31 of 31 nights at Sligo have civil darkness, and 5% of past December days reached Kp 5.

How dark is Sligo in December?

Sligo averages 15.0 hours of civil night a night in December 2026, from 14 h 45 min on the 1st to 14 h 59 min on the last night.

How cloudy is Sligo in December?

NASA POWER's 2001 to 2020 climatology gives Sligo's 1 degree cell 83% mean cloud in December, against 81% for the whole year. It is an all-hours average, not a forecast.

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

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

Is December or January better in Sligo?

By civil night times the clear share, December scores 2.6 hours at Sligo and January 2.3. December comes out ahead.

Sligo · December 2026

Northern lights in Sligo in December 2026

Answer

December gives Sligo 15.1 hours of civil night on the 15th, the darkest month of its year, under 83% mean cloud. 5% of December days since 1996 reached Kp 5, enough for the oval edge to reach Sligo.

15.0 h

civil night, average night

SunCalc for 54.27, -8.47; NASA POWER; GFZ Kp

December against the rest of the year

2.3

2.1

2.0

1.5

0.9

0.8

1.3

2.0

2.6

2.5

2.6

December cloud at Sligo averages 83% in NASA POWER's 2001 to 2020 record, 2 points cloudier than its yearly mean. May is Sligo's clearest month at 76%. That makes December the best month of Sligo's year by civil night times clear sky, 2.6 hours. Belfast, 168 km away, averages 80%, clearer by 3 points.

Civil night at Sligo starts December at 14 h 45 min and reaches 14 h 59 min by December 31 as the nights lengthen by 0.2 hours. SWPC's 10 PM to 2 AM window is fully dark on every night. True astronomical darkness, the sun 18 degrees down, lasts 12.1 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/Dublin dates. Sligo gets 250 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
42% lit
8.0 h
2
32% lit
9.3 h
3
23% lit
10.7 h
4
15% lit
12.0 h
5
9% lit
13.3 h
6
4% lit
14.7 h
7
1% lit
14.9 h
8
0% lit
14.9 h
9
1% lit
14.9 h
New
10
4% lit
15.0 h
11
8% lit
14.1 h
12
13% lit
12.8 h
13
21% lit
11.6 h
14
29% lit
10.3 h
15
38% lit
9.1 h
16
48% lit
7.8 h
17
58% lit
6.5 h
18
68% lit
5.2 h
19
78% lit
3.7 h
20
87% lit
2.1 h
21
94% lit
0.6 h
22
98% lit
0.0 h
23
100% lit
0.0 h
24
99% lit
0.0 h
Full
25
94% lit
1.0 h
26
88% lit
2.6 h
27
79% lit
4.2 h
28
69% lit
5.6 h
29
58% lit
7.0 h
30
48% lit
8.4 h
31
38% lit
9.7 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

Sligo needs Kp 5 for the average oval edge to sit overhead. 44 of the 930 December days from 1996 to 2025 (5%) 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%. Sligo sits at 57.3 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.

December across Ireland

No month-page town in Ireland has more civil night on December 15 than Sligo; the national median is 14.9 hours. Coming from November (14.1 hours at Sligo), December adds darkness, and January brings shorter nights (14.5 hours on the 15th). The December solstice falls on December 21, 20:49 Sligo time.

Civil night on December 15 and December cloud, month-page towns in Ireland
Town	Civil night	Cloud
Sligo	15.1 h	83%
Dublin	14.9 h	76%
Limerick	14.8 h	76%
Cork	14.7 h	72%

Darkness and moon, every night

Sligo, 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	14 h 45 min	11 h 48 min	7 h 59 min	3 h	42%
Wed Dec 2	14 h 47 min	11 h 50 min	9 h 20 min	4 h	32%
Thu Dec 3	14 h 48 min	11 h 52 min	10 h 40 min	4 h	23%
Fri Dec 4	14 h 50 min	11 h 53 min	12 h 1 min	4 h	15%
Sat Dec 5	14 h 52 min	11 h 54 min	13 h 21 min	4 h	9%
Sun Dec 6	14 h 53 min	11 h 56 min	14 h 40 min	4 h	4%
Mon Dec 7	14 h 55 min	11 h 57 min	14 h 55 min	4 h	1%
Tue Dec 8	14 h 56 min	11 h 58 min	14 h 56 min	4 h	0%
Wed Dec 9	14 h 57 min	11 h 59 min	14 h 57 min	4 h	1%
Thu Dec 10	14 h 59 min	12 h	14 h 59 min	4 h	4%
Fri Dec 11	15 h	12 h 1 min	14 h 5 min	4 h	8%
Sat Dec 12	15 h 1 min	12 h 2 min	12 h 51 min	4 h	13%
Sun Dec 13	15 h 2 min	12 h 3 min	11 h 35 min	4 h	21%
Mon Dec 14	15 h 2 min	12 h 3 min	10 h 20 min	4 h	29%
Tue Dec 15	15 h 3 min	12 h 4 min	9 h 5 min	3 h 4 min	38%
Wed Dec 16	15 h 4 min	12 h 4 min	7 h 49 min	1 h 47 min	48%
Thu Dec 17	15 h 4 min	12 h 5 min	6 h 31 min	29 min	58%
Fri Dec 18	15 h 4 min	12 h 5 min	5 h 9 min	0 min	68%
Sat Dec 19	15 h 5 min	12 h 5 min	3 h 41 min	0 min	78%
Sun Dec 20	15 h 5 min	12 h 5 min	2 h 9 min	0 min	87%
Mon Dec 21	15 h 5 min	12 h 5 min	37 min	0 min	94%
Tue Dec 22	15 h 5 min	12 h 5 min	0 min	0 min	98%
Wed Dec 23	15 h 5 min	12 h 5 min	0 min	0 min	100%
Thu Dec 24	15 h 4 min	12 h 5 min	0 min	0 min	99%
Fri Dec 25	15 h 4 min	12 h 4 min	1 h 1 min	0 min	94%
Sat Dec 26	15 h 3 min	12 h 4 min	2 h 38 min	0 min	88%
Sun Dec 27	15 h 3 min	12 h 4 min	4 h 11 min	0 min	79%
Mon Dec 28	15 h 2 min	12 h 3 min	5 h 38 min	43 min	69%
Tue Dec 29	15 h 1 min	12 h 2 min	7 h 1 min	2 h 7 min	58%
Wed Dec 30	15 h	12 h 2 min	8 h 22 min	3 h 28 min	48%
Thu Dec 31	14 h 59 min	12 h 1 min	9 h 42 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 Sligo in December?: On dark, clear nights with enough activity. 31 of 31 nights at Sligo have civil darkness, and 5% of past December days reached Kp 5.
How dark is Sligo in December?: Sligo averages 15.0 hours of civil night a night in December 2026, from 14 h 45 min on the 1st to 14 h 59 min on the last night.
How cloudy is Sligo in December?: NASA POWER's 2001 to 2020 climatology gives Sligo's 1 degree cell 83% mean cloud in December, against 81% for the whole year. It is an all-hours average, not a forecast.
What is the best night in December 2026 for aurora in Sligo?: By darkness and moon alone, Dec 2, with 4 h of moon-free darkness inside 10 PM to 2 AM at Sligo. Activity on that date will only be known hours ahead.
Is December or January better in Sligo?: By civil night times the clear share, December scores 2.6 hours at Sligo and January 2.3. 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.