Can you see the northern lights in Kalundborg in April?

On dark, clear nights with enough activity. 30 of 30 nights at Kalundborg have civil darkness, and 4% of past April days reached Kp 6.

How dark is Kalundborg in April?

Kalundborg averages 8.3 hours of civil night a night in April 2027, from 9 h 29 min on the 1st to 7 h 6 min on the last night.

How cloudy is Kalundborg in April?

NASA POWER's 2001 to 2020 climatology gives Kalundborg's 1 degree cell 57% mean cloud in April, against 68% for the whole year. It is an all-hours average, not a forecast.

What is the best night in April 2027 for aurora in Kalundborg?

By darkness and moon alone, Apr 1, with 4 h of moon-free darkness inside 10 PM to 2 AM at Kalundborg. Activity on that date will only be known hours ahead.

Is April or May better in Kalundborg?

By civil night times the clear share, April scores 3.6 hours at Kalundborg and May 2.4. April comes out ahead.

Kalundborg · April 2027

Northern lights in Kalundborg in April 2027

Answer

April gives Kalundborg 8.3 hours of civil night on the 15th, the 8th darkest of its 12 months, under 57% mean cloud. 4% of April days since 1996 reached Kp 6, enough for the oval edge to reach Kalundborg.

8.3 h

civil night, average night

SunCalc for 55.68, 11.09; NASA POWER; GFZ Kp

April against the rest of the year

2.9

2.8

3.5

3.6

2.4

1.6

1.9

2.7

3.8

3.9

3.4

3.2

April cloud at Kalundborg averages 57% in NASA POWER's 2001 to 2020 record, 11 points clearer than its yearly mean. No month at Kalundborg is clearer. By civil night times clear sky, April scores 3.6 hours at Kalundborg, 3rd of 12. Odense, 54 km away, averages the same 57%.

Civil night at Kalundborg starts April at 9 h 29 min and reaches 7 h 6 min by April 30, 2.4 hours shorter. SWPC's 10 PM to 2 AM window is fully dark on every night. True astronomical darkness, the sun 18 degrees down, lasts 4.5 hours on the 15th.

April night by night

April opens toward a new moon on Apr 7, with full moon on Apr 21, in Europe/Copenhagen dates. Kalundborg gets 135 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: Apr 1 (4 h), Apr 2 (4 h), Apr 3 (4 h).

1
24% lit
9.0 h
2
16% lit
9.1 h
3
10% lit
9.2 h
4
5% lit
9.3 h
5
1% lit
9.2 h
6
0% lit
9.1 h
7
1% lit
8.5 h
New
8
5% lit
6.9 h
9
10% lit
5.4 h
10
18% lit
3.9 h
11
28% lit
2.7 h
12
38% lit
1.9 h
13
50% lit
1.4 h
14
61% lit
1.0 h
15
72% lit
0.8 h
16
81% lit
0.6 h
17
89% lit
0.4 h
18
95% lit
0.2 h
19
99% lit
0.0 h
20
100% lit
0.0 h
21
99% lit
0.8 h
Full
22
96% lit
2.2 h
23
91% lit
3.4 h
24
84% lit
4.5 h
25
76% lit
5.2 h
26
68% lit
5.6 h
27
59% lit
5.9 h
28
49% lit
6.1 h
29
40% lit
6.2 h
30
31% lit
6.3 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 Aprils

Kalundborg needs Kp 6 for the average oval edge to sit overhead. 37 of the 900 April days from 1996 to 2025 (4%) reached it in the GFZ Potsdam record, 5th of 12 months; storm days with Kp 5 or more made up 12%. Kalundborg sits at 55.6 degrees geomagnetic. By SWPC's rule the average oval edge is overhead at Kp 6, and aurora is usually visible on the northern horizon at G1 (Kp 5) or less.

April across Denmark

Kalundborg ranks 2nd in Denmark for civil night on April 15, behind Odense at 8.4 hours. Coming from March (10.8 hours at Kalundborg), April loses darkness, and May brings shorter nights (5.9 hours on the 15th).

Civil night on April 15 and April cloud, month-page towns in Denmark
Town	Civil night	Cloud
Odense	8.4 h	57%
Kalundborg	8.3 h	57%
Copenhagen	8.3 h	59%
Århus	8.3 h	61%
Aalborg	8.1 h	67%

Darkness and moon, every night

Kalundborg, April 2027: each night from local noon to the next noon
Night	Civil	Astronomical	Moon-free dark	Moon-free, 10 PM to 2 AM	Moon lit
Thu Apr 1	9 h 29 min	6 h 13 min	9 h	4 h	24%
Fri Apr 2	9 h 24 min	6 h 7 min	9 h 6 min	4 h	16%
Sat Apr 3	9 h 20 min	6 h	9 h 11 min	4 h	10%
Sun Apr 4	9 h 15 min	5 h 54 min	9 h 15 min	4 h	5%
Mon Apr 5	9 h 10 min	5 h 47 min	9 h 10 min	4 h	1%
Tue Apr 6	9 h 5 min	5 h 40 min	9 h 5 min	4 h	0%
Wed Apr 7	9 h	5 h 33 min	8 h 29 min	4 h	1%
Thu Apr 8	8 h 55 min	5 h 26 min	6 h 56 min	3 h 12 min	5%
Fri Apr 9	8 h 50 min	5 h 19 min	5 h 23 min	1 h 41 min	10%
Sat Apr 10	8 h 45 min	5 h 12 min	3 h 55 min	16 min	18%
Sun Apr 11	8 h 40 min	5 h 4 min	2 h 44 min	0 min	28%
Mon Apr 12	8 h 35 min	4 h 57 min	1 h 55 min	0 min	38%
Tue Apr 13	8 h 30 min	4 h 49 min	1 h 23 min	0 min	50%
Wed Apr 14	8 h 26 min	4 h 41 min	1 h 1 min	0 min	61%
Thu Apr 15	8 h 21 min	4 h 33 min	46 min	0 min	72%
Fri Apr 16	8 h 16 min	4 h 24 min	33 min	0 min	81%
Sat Apr 17	8 h 11 min	4 h 16 min	22 min	0 min	89%
Sun Apr 18	8 h 6 min	4 h 7 min	11 min	0 min	95%
Mon Apr 19	8 h 1 min	3 h 58 min	0 min	0 min	99%
Tue Apr 20	7 h 56 min	3 h 49 min	0 min	0 min	100%
Wed Apr 21	7 h 51 min	3 h 40 min	48 min	7 min	99%
Thu Apr 22	7 h 46 min	3 h 30 min	2 h 11 min	1 h 32 min	96%
Fri Apr 23	7 h 41 min	3 h 19 min	3 h 26 min	2 h 50 min	91%
Sat Apr 24	7 h 36 min	3 h 9 min	4 h 27 min	3 h 52 min	84%
Sun Apr 25	7 h 31 min	2 h 57 min	5 h 10 min	4 h	76%
Mon Apr 26	7 h 26 min	2 h 46 min	5 h 37 min	4 h	68%
Tue Apr 27	7 h 21 min	2 h 33 min	5 h 54 min	4 h	59%
Wed Apr 28	7 h 16 min	2 h 19 min	6 h 5 min	4 h	49%
Thu Apr 29	7 h 11 min	2 h 4 min	6 h 13 min	4 h	40%
Fri Apr 30	7 h 6 min	1 h 47 min	6 h 18 min	4 h	31%

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

Questions

Can you see the northern lights in Kalundborg in April?: On dark, clear nights with enough activity. 30 of 30 nights at Kalundborg have civil darkness, and 4% of past April days reached Kp 6.
How dark is Kalundborg in April?: Kalundborg averages 8.3 hours of civil night a night in April 2027, from 9 h 29 min on the 1st to 7 h 6 min on the last night.
How cloudy is Kalundborg in April?: NASA POWER's 2001 to 2020 climatology gives Kalundborg's 1 degree cell 57% mean cloud in April, against 68% for the whole year. It is an all-hours average, not a forecast.
What is the best night in April 2027 for aurora in Kalundborg?: By darkness and moon alone, Apr 1, with 4 h of moon-free darkness inside 10 PM to 2 AM at Kalundborg. Activity on that date will only be known hours ahead.
Is April or May better in Kalundborg?: By civil night times the clear share, April scores 3.6 hours at Kalundborg and May 2.4. April 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.