Can you see the northern lights in Juneau in May?

On dark, clear nights with enough activity. 31 of 31 nights at Juneau have civil darkness, and 47% of past May days reached Kp 3.

How dark is Juneau in May?

Juneau averages 5.0 hours of civil night a night in May 2027, from 6 h 25 min on the 1st to 3 h 39 min on the last night.

How cloudy is Juneau in May?

NASA POWER's 2001 to 2020 climatology gives Juneau's 1 degree cell 74% mean cloud in May, against 79% for the whole year. It is an all-hours average, not a forecast.

What is the best night in May 2027 for aurora in Juneau?

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

Is May or June better in Juneau?

By civil night times the clear share, May scores 1.3 hours at Juneau and June 0.5. May comes out ahead.

Juneau · May 2027

Northern lights in Juneau in May 2027

Answer

May gives Juneau 5.1 hours of civil night on the 15th, the 10th darkest of its 12 months, under 74% mean cloud. 47% of May days since 1996 reached Kp 3, enough for the oval edge to reach Juneau.

5.0 h

civil night, average night

SunCalc for 58.30, -134.42; NASA POWER; GFZ Kp

May against the rest of the year

3.0

3.3

2.6

2.0

1.3

0.5

0.8

1.4

1.9

2.3

3.0

3.1

May cloud at Juneau averages 74% in NASA POWER's 2001 to 2020 record, 5 points clearer than its yearly mean. No month at Juneau is clearer. By civil night times clear sky, May scores 1.3 hours at Juneau, 10th of 12. Whitehorse, 271 km away, averages 71%, clearer by 3 points.

Civil night at Juneau starts May at 6 h 25 min and reaches 3 h 39 min by May 31, 2.8 hours shorter. The 10 PM to 2 AM window is fully dark on 7 of 31 nights. The sun never reaches 18 degrees down, so Juneau gets no astronomical night in May.

May night by night

May opens toward a new moon on May 6, with full moon on May 20, in America/Juneau dates. Juneau gets 81 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: May 1 (4 h), May 2 (4 h), May 3 (4 h).

1
19% lit
6.1 h
2
11% lit
6.2 h
3
6% lit
6.2 h
4
2% lit
6.1 h
5
0% lit
6.0 h
6
1% lit
5.3 h
New
7
5% lit
3.7 h
8
11% lit
2.5 h
9
19% lit
1.8 h
10
29% lit
1.3 h
11
40% lit
1.1 h
12
52% lit
0.9 h
13
63% lit
0.7 h
14
73% lit
0.6 h
15
82% lit
0.5 h
16
90% lit
0.4 h
17
95% lit
0.2 h
18
98% lit
0.0 h
19
100% lit
0.0 h
20
99% lit
0.6 h
Full
21
96% lit
1.6 h
22
92% lit
2.3 h
23
86% lit
2.6 h
24
79% lit
2.8 h
25
71% lit
2.9 h
26
62% lit
3.0 h
27
53% lit
3.0 h
28
43% lit
3.0 h
29
33% lit
3.0 h
30
24% lit
3.1 h
31
15% lit
3.1 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 Mays

Juneau needs Kp 3 for the average oval edge to sit overhead. 436 of the 930 May days from 1996 to 2025 (47%) reached it in the GFZ Potsdam record, 9th of 12 months; storm days with Kp 5 or more made up 10%. Juneau sits at 61.6 degrees geomagnetic, inside SWPC's 60 to 75 degree band, where aurora can be seen on more than half of all nights. No storm is needed: by SWPC's rule the average oval edge is overhead at Kp 3.

May across United States

Juneau ranks 7th in United States for civil night on May 15, behind Buffalo at 8.1 hours. Coming from April (7.9 hours at Juneau), May loses darkness, and June brings shorter nights (2.8 hours on the 15th).

Civil night on May 15 and May cloud, month-page towns in United States
Town	Civil night	Cloud
Buffalo	8.1 h	65%
Portland, Maine	8.0 h	66%
Minneapolis	7.9 h	63%
Duluth	7.6 h	65%
Fargo	7.6 h	61%
Seattle	7.5 h	70%
Juneau	5.1 h	74%
Anchorage	3.8 h	79%
Eagle River	3.7 h	79%
Fairbanks	0.0 h	70%

Darkness and moon, every night

Juneau, May 2027: each night from local noon to the next noon
Night	Civil	Moon-free dark	Moon-free, 10 PM to 2 AM	Moon lit
Sat May 1	6 h 25 min	6 h 8 min	4 h	19%
Sun May 2	6 h 19 min	6 h 9 min	4 h	11%
Mon May 3	6 h 13 min	6 h 11 min	4 h	6%
Tue May 4	6 h 8 min	6 h 8 min	4 h	2%
Wed May 5	6 h 2 min	6 h 2 min	4 h	0%
Thu May 6	5 h 56 min	5 h 16 min	3 h 24 min	1%
Fri May 7	5 h 50 min	3 h 42 min	1 h 53 min	5%
Sat May 8	5 h 44 min	2 h 29 min	43 min	11%
Sun May 9	5 h 39 min	1 h 45 min	2 min	19%
Mon May 10	5 h 33 min	1 h 19 min	0 min	29%
Tue May 11	5 h 27 min	1 h 4 min	0 min	40%
Wed May 12	5 h 21 min	53 min	0 min	52%
Thu May 13	5 h 16 min	44 min	0 min	63%
Fri May 14	5 h 10 min	37 min	0 min	73%
Sat May 15	5 h 4 min	30 min	0 min	82%
Sun May 16	4 h 59 min	23 min	0 min	90%
Mon May 17	4 h 53 min	14 min	0 min	95%
Tue May 18	4 h 47 min	1 min	0 min	98%
Wed May 19	4 h 42 min	0 min	0 min	100%
Thu May 20	4 h 36 min	37 min	37 min	99%
Fri May 21	4 h 31 min	1 h 39 min	1 h 39 min	96%
Sat May 22	4 h 25 min	2 h 18 min	2 h 18 min	92%
Sun May 23	4 h 20 min	2 h 39 min	2 h 39 min	86%
Mon May 24	4 h 15 min	2 h 50 min	2 h 50 min	79%
Tue May 25	4 h 9 min	2 h 56 min	2 h 56 min	71%
Wed May 26	4 h 4 min	2 h 59 min	2 h 59 min	62%
Thu May 27	3 h 59 min	3 h	3 h	53%
Fri May 28	3 h 54 min	3 h 1 min	3 h 1 min	43%
Sat May 29	3 h 49 min	3 h 2 min	2 h 59 min	33%
Sun May 30	3 h 44 min	3 h 4 min	2 h 57 min	24%
Mon May 31	3 h 39 min	3 h 7 min	2 h 54 min	15%

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

Questions

Can you see the northern lights in Juneau in May?: On dark, clear nights with enough activity. 31 of 31 nights at Juneau have civil darkness, and 47% of past May days reached Kp 3.
How dark is Juneau in May?: Juneau averages 5.0 hours of civil night a night in May 2027, from 6 h 25 min on the 1st to 3 h 39 min on the last night.
How cloudy is Juneau in May?: NASA POWER's 2001 to 2020 climatology gives Juneau's 1 degree cell 74% mean cloud in May, against 79% for the whole year. It is an all-hours average, not a forecast.
What is the best night in May 2027 for aurora in Juneau?: By darkness and moon alone, May 1, with 4 h of moon-free darkness inside 10 PM to 2 AM at Juneau. Activity on that date will only be known hours ahead.
Is May or June better in Juneau?: By civil night times the clear share, May scores 1.3 hours at Juneau and June 0.5. May 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.