Can you see the northern lights in Danbury in April?

On dark, clear nights with enough activity. 30 of 30 nights at Danbury have civil darkness, and 1% of past April days reached Kp 8.

How dark is Danbury in April?

Danbury averages 9.6 hours of civil night a night in April 2027, from 10 h 16 min on the 1st to 8 h 55 min on the last night.

How cloudy is Danbury in April?

NASA POWER's 2001 to 2020 climatology gives Danbury's 1 degree cell 62% mean cloud in April, against 59% for the whole year. It is an all-hours average, not a forecast.

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

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

Is April or May better in Danbury?

By civil night times the clear share, April scores 3.6 hours at Danbury and May 3.0. April comes out ahead.

Danbury · April 2027

Northern lights in Danbury in April 2027

Answer

April gives Danbury 9.6 hours of civil night on the 15th, the 8th darkest of its 12 months, under 62% mean cloud. 1% of April days since 1996 reached Kp 8, enough for the oval edge to reach Danbury.

9.6 h

civil night, average night

SunCalc for 41.39, -73.45; NASA POWER; GFZ Kp

April against the rest of the year

4.8

4.7

4.2

3.6

3.0

3.1

3.6

4.2

5.3

5.0

5.4

4.8

April cloud at Danbury averages 62% in NASA POWER's 2001 to 2020 record, 3 points cloudier than its yearly mean. September is Danbury's clearest month at 50%. By civil night times clear sky, April scores 3.6 hours at Danbury, 9th of 12. Portland, Maine, 363 km away, averages the same 62%.

Civil night at Danbury starts April at 10 h 16 min and reaches 8 h 55 min by April 30, 1.4 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 7.2 hours on the 15th.

April night by night

April opens toward a new moon on Apr 6, with full moon on Apr 20, in America/New_York dates. Danbury gets 150 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
22% lit
8.8 h
2
15% lit
9.1 h
3
8% lit
9.4 h
4
4% lit
9.8 h
5
1% lit
10.1 h
6
0% lit
10.0 h
New
7
2% lit
9.3 h
8
6% lit
8.1 h
9
12% lit
6.8 h
10
20% lit
5.6 h
11
30% lit
4.6 h
12
41% lit
3.6 h
13
53% lit
2.9 h
14
64% lit
2.3 h
15
74% lit
1.8 h
16
84% lit
1.4 h
17
91% lit
0.9 h
18
96% lit
0.5 h
19
99% lit
0.1 h
20
100% lit
0.0 h
Full
21
98% lit
0.8 h
22
94% lit
1.9 h
23
89% lit
3.0 h
24
82% lit
3.9 h
25
74% lit
4.7 h
26
66% lit
5.3 h
27
57% lit
5.8 h
28
47% lit
6.2 h
29
38% lit
6.6 h
30
29% lit
7.0 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 Aprils

Danbury needs Kp 8 for the average oval edge to sit overhead. 5 of the 900 April days from 1996 to 2025 (1%) reached it in the GFZ Potsdam record, 4th of 12 months; storm days with Kp 5 or more made up 12%. Danbury sits at 50.6 degrees geomagnetic. The lowest NOAA storm level whose typical viewing latitude reaches it is G3 (Kp = 7). By SWPC's rule the average oval edge is overhead only at Kp 8.

April across United States

No month-page town in United States has more civil night on April 15 than Danbury; the national median is 9.2 hours. Coming from March (11.1 hours at Danbury), April loses darkness, and May brings shorter nights (8.3 hours on the 15th).

Civil night on April 15 and April cloud, month-page towns in United States
Town	Civil night	Cloud
Danbury	9.6 h	62%
Buffalo	9.5 h	69%
Portland, Maine	9.4 h	62%
Minneapolis	9.3 h	61%
Duluth	9.2 h	64%
Fargo	9.2 h	61%
Seattle	9.1 h	75%
Juneau	7.9 h	75%
Anchorage	7.4 h	72%
Eagle River	7.4 h	72%
Fairbanks	6.6 h	59%

Darkness and moon, every night

Danbury, 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	10 h 16 min	8 h 1 min	8 h 45 min	4 h	22%
Fri Apr 2	10 h 13 min	7 h 57 min	9 h 6 min	4 h	15%
Sat Apr 3	10 h 10 min	7 h 54 min	9 h 26 min	4 h	8%
Sun Apr 4	10 h 7 min	7 h 51 min	9 h 46 min	4 h	4%
Mon Apr 5	10 h 4 min	7 h 47 min	10 h 4 min	4 h	1%
Tue Apr 6	10 h 1 min	7 h 44 min	10 h 1 min	4 h	0%
Wed Apr 7	9 h 58 min	7 h 41 min	9 h 21 min	4 h	2%
Thu Apr 8	9 h 56 min	7 h 37 min	8 h 6 min	4 h	6%
Fri Apr 9	9 h 53 min	7 h 34 min	6 h 51 min	2 h 59 min	12%
Sat Apr 10	9 h 50 min	7 h 31 min	5 h 38 min	1 h 49 min	20%
Sun Apr 11	9 h 47 min	7 h 27 min	4 h 34 min	46 min	30%
Mon Apr 12	9 h 44 min	7 h 24 min	3 h 39 min	0 min	41%
Tue Apr 13	9 h 42 min	7 h 20 min	2 h 55 min	0 min	53%
Wed Apr 14	9 h 39 min	7 h 17 min	2 h 19 min	0 min	64%
Thu Apr 15	9 h 36 min	7 h 13 min	1 h 49 min	0 min	74%
Fri Apr 16	9 h 33 min	7 h 10 min	1 h 22 min	0 min	84%
Sat Apr 17	9 h 30 min	7 h 6 min	57 min	0 min	91%
Sun Apr 18	9 h 28 min	7 h 3 min	32 min	0 min	96%
Mon Apr 19	9 h 25 min	6 h 59 min	6 min	0 min	99%
Tue Apr 20	9 h 22 min	6 h 56 min	0 min	0 min	100%
Wed Apr 21	9 h 19 min	6 h 53 min	49 min	0 min	98%
Thu Apr 22	9 h 17 min	6 h 49 min	1 h 56 min	10 min	94%
Fri Apr 23	9 h 14 min	6 h 46 min	2 h 58 min	1 h 13 min	89%
Sat Apr 24	9 h 11 min	6 h 42 min	3 h 53 min	2 h 9 min	82%
Sun Apr 25	9 h 8 min	6 h 39 min	4 h 39 min	2 h 56 min	74%
Mon Apr 26	9 h 6 min	6 h 35 min	5 h 17 min	3 h 36 min	66%
Tue Apr 27	9 h 3 min	6 h 32 min	5 h 48 min	4 h	57%
Wed Apr 28	9 h	6 h 28 min	6 h 14 min	4 h	47%
Thu Apr 29	8 h 58 min	6 h 25 min	6 h 37 min	4 h	38%
Fri Apr 30	8 h 55 min	6 h 21 min	6 h 57 min	4 h	29%

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

Questions

Can you see the northern lights in Danbury in April?: On dark, clear nights with enough activity. 30 of 30 nights at Danbury have civil darkness, and 1% of past April days reached Kp 8.
How dark is Danbury in April?: Danbury averages 9.6 hours of civil night a night in April 2027, from 10 h 16 min on the 1st to 8 h 55 min on the last night.
How cloudy is Danbury in April?: NASA POWER's 2001 to 2020 climatology gives Danbury's 1 degree cell 62% mean cloud in April, against 59% for the whole year. It is an all-hours average, not a forecast.
What is the best night in April 2027 for aurora in Danbury?: By darkness and moon alone, Apr 1, with 4 h of moon-free darkness inside 10 PM to 2 AM at Danbury. Activity on that date will only be known hours ahead.
Is April or May better in Danbury?: By civil night times the clear share, April scores 3.6 hours at Danbury and May 3.0. 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.