Can you see the northern lights in Brockton in December?

On dark, clear nights with enough activity. 31 of 31 nights at Brockton have civil darkness, and 0% of past December days reached Kp 8.

How dark is Brockton in December?

Brockton averages 13.7 hours of civil night a night in December 2026, from 13 h 32 min on the 1st to 13 h 41 min on the last night.

How cloudy is Brockton in December?

NASA POWER's 2001 to 2020 climatology gives Brockton's 1 degree cell 63% mean cloud in December, against 59% for the whole year. It is an all-hours average, not a forecast.

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

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

Is December or January better in Brockton?

By civil night times the clear share, December scores 5.1 hours at Brockton and January 5.1. January comes out ahead.

Brockton · December 2026

Northern lights in Brockton in December 2026

Answer

December gives Brockton 13.7 hours of civil night on the 15th, the darkest month of its year, under 63% mean cloud. 0% of December days since 1996 reached Kp 8, enough for the oval edge to reach Brockton.

13.7 h

civil night, average night

SunCalc for 42.08, -71.02; NASA POWER; GFZ Kp

December against the rest of the year

5.1

4.8

4.3

3.7

3.0

2.9

3.6

4.3

5.1

4.9

5.2

5.1

December cloud at Brockton averages 63% in NASA POWER's 2001 to 2020 record, 4 points cloudier than its yearly mean. September is Brockton's clearest month at 51%. By civil night times clear sky, December scores 5.1 hours at Brockton, 4th of 12. Portland, Maine, 186 km away, averages 66%, cloudier by 3 points.

Civil night at Brockton starts December at 13 h 32 min and reaches 13 h 41 min by December 31 as the nights lengthen by 0.1 hours. SWPC's 10 PM to 2 AM window is fully dark on every night. True astronomical darkness, the sun 18 degrees down, lasts 11.4 hours on the 15th.

December night by night

December opens toward a new moon on Dec 8, with full moon on Dec 23, in America/New_York dates. Brockton gets 228 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
40% lit
7.6 h
2
30% lit
8.8 h
3
21% lit
9.9 h
4
14% lit
11.0 h
5
8% lit
12.1 h
6
3% lit
13.2 h
7
1% lit
13.7 h
8
0% lit
13.7 h
New
9
1% lit
13.7 h
10
4% lit
13.2 h
11
9% lit
12.2 h
12
15% lit
11.1 h
13
22% lit
10.1 h
14
31% lit
9.0 h
15
40% lit
8.0 h
16
50% lit
6.9 h
17
60% lit
5.8 h
18
70% lit
4.7 h
19
80% lit
3.5 h
20
88% lit
2.2 h
21
95% lit
0.9 h
22
99% lit
0.0 h
23
100% lit
0.0 h
Full
24
98% lit
0.1 h
25
93% lit
1.5 h
26
86% lit
2.8 h
27
77% lit
4.1 h
28
67% lit
5.3 h
29
56% lit
6.5 h
30
46% lit
7.6 h
31
36% lit
8.7 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

Brockton needs Kp 8 for the average oval edge to sit overhead. 1 of the 930 December days from 1996 to 2025 (0%) 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%. Brockton sits at 51.3 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.

December across United States

Brockton ranks 11th in United States for civil night on December 15, behind Fairbanks at 17.2 hours. Coming from November (13.1 hours at Brockton), December adds darkness, and January brings shorter nights (13.4 hours on the 15th). The December solstice falls on December 21, 15:49 Brockton time.

Civil night on December 15 and December cloud, month-page towns in United States
Town	Civil night	Cloud
Fairbanks	17.2 h	59%
Anchorage	16.3 h	72%
Eagle River	16.3 h	72%
Juneau	15.7 h	80%
Seattle	14.3 h	79%
Duluth	14.2 h	71%
Fargo	14.2 h	68%
Minneapolis	14.0 h	69%
Portland, Maine	13.9 h	66%
Buffalo	13.8 h	85%
Brockton	13.7 h	63%

Darkness and moon, every night

Brockton, 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	13 h 32 min	11 h 16 min	7 h 38 min	2 h 26 min	40%
Wed Dec 2	13 h 34 min	11 h 17 min	8 h 46 min	3 h 33 min	30%
Thu Dec 3	13 h 35 min	11 h 18 min	9 h 52 min	4 h	21%
Fri Dec 4	13 h 36 min	11 h 19 min	10 h 59 min	4 h	14%
Sat Dec 5	13 h 37 min	11 h 20 min	12 h 5 min	4 h	8%
Sun Dec 6	13 h 38 min	11 h 20 min	13 h 10 min	4 h	3%
Mon Dec 7	13 h 39 min	11 h 21 min	13 h 39 min	4 h	1%
Tue Dec 8	13 h 39 min	11 h 22 min	13 h 39 min	4 h	0%
Wed Dec 9	13 h 40 min	11 h 23 min	13 h 40 min	4 h	1%
Thu Dec 10	13 h 41 min	11 h 23 min	13 h 10 min	4 h	4%
Fri Dec 11	13 h 42 min	11 h 24 min	12 h 10 min	4 h	9%
Sat Dec 12	13 h 42 min	11 h 24 min	11 h 8 min	4 h	15%
Sun Dec 13	13 h 43 min	11 h 25 min	10 h 5 min	4 h	22%
Mon Dec 14	13 h 43 min	11 h 25 min	9 h 2 min	4 h	31%
Tue Dec 15	13 h 44 min	11 h 25 min	8 h	3 h 28 min	40%
Wed Dec 16	13 h 44 min	11 h 26 min	6 h 56 min	2 h 24 min	50%
Thu Dec 17	13 h 44 min	11 h 26 min	5 h 50 min	1 h 18 min	60%
Fri Dec 18	13 h 44 min	11 h 26 min	4 h 41 min	8 min	70%
Sat Dec 19	13 h 45 min	11 h 26 min	3 h 27 min	0 min	80%
Sun Dec 20	13 h 45 min	11 h 26 min	2 h 10 min	0 min	88%
Mon Dec 21	13 h 45 min	11 h 26 min	52 min	0 min	95%
Tue Dec 22	13 h 45 min	11 h 26 min	0 min	0 min	99%
Wed Dec 23	13 h 44 min	11 h 26 min	0 min	0 min	100%
Thu Dec 24	13 h 44 min	11 h 26 min	8 min	0 min	98%
Fri Dec 25	13 h 44 min	11 h 26 min	1 h 29 min	0 min	93%
Sat Dec 26	13 h 44 min	11 h 25 min	2 h 50 min	0 min	86%
Sun Dec 27	13 h 43 min	11 h 25 min	4 h 7 min	0 min	77%
Mon Dec 28	13 h 43 min	11 h 25 min	5 h 19 min	13 min	67%
Tue Dec 29	13 h 42 min	11 h 24 min	6 h 28 min	1 h 23 min	56%
Wed Dec 30	13 h 42 min	11 h 24 min	7 h 35 min	2 h 31 min	46%
Thu Dec 31	13 h 41 min	11 h 23 min	8 h 41 min	3 h 38 min	36%

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

Questions

Can you see the northern lights in Brockton in December?: On dark, clear nights with enough activity. 31 of 31 nights at Brockton have civil darkness, and 0% of past December days reached Kp 8.
How dark is Brockton in December?: Brockton averages 13.7 hours of civil night a night in December 2026, from 13 h 32 min on the 1st to 13 h 41 min on the last night.
How cloudy is Brockton in December?: NASA POWER's 2001 to 2020 climatology gives Brockton's 1 degree cell 63% mean cloud in December, against 59% for the whole year. It is an all-hours average, not a forecast.
What is the best night in December 2026 for aurora in Brockton?: By darkness and moon alone, Dec 3, with 4 h of moon-free darkness inside 10 PM to 2 AM at Brockton. Activity on that date will only be known hours ahead.
Is December or January better in Brockton?: By civil night times the clear share, December scores 5.1 hours at Brockton and January 5.1. January 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.