Can you see the northern lights in Harstad in May?

Not in May 2027. The sun stays above -6 degrees every night at Harstad, so there is no civil darkness.

How dark is Harstad in May?

Harstad averages 0.0 hours of civil night a night in May 2027, from 0 min on the 1st to 0 min on the last night.

How cloudy is Harstad in May?

NASA POWER's 2001 to 2020 climatology gives Harstad's 1 degree cell 80% mean cloud in May, against 81% for the whole year. It is an all-hours average, not a forecast.

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

No night in May 2027 has moon-free darkness inside 10 PM to 2 AM at Harstad.

Is May or June better in Harstad?

By civil night times the clear share, May scores 0.0 hours at Harstad and June 0.0. They are level.

Harstad · May 2027

Northern lights in Harstad in May 2027

Answer

Harstad has no civil darkness in May 2027: the sun stays above -6 degrees on all 31 nights. SWPC notes that "It must also be dark so during the summer months at auroral latitudes, the midnight sun prevents auroral observations."

0.0 h

civil night, average night

SunCalc for 68.80, 16.54; NASA POWER; GFZ Kp

May against the rest of the year

3.5

2.6

1.7

1.0

0.0

0.5

1.5

2.5

3.0

3.2

May cloud at Harstad averages 80% in NASA POWER's 2001 to 2020 record, close to its yearly mean of 81%. July is Harstad's clearest month at 78%. By civil night times clear sky, May scores 0.0 hours at Harstad, 10th of 12. Tromsø, 134 km away, averages the same 80%.

The sun never gets 6 degrees below the horizon at Harstad in May 2027, so every night is twilight or daylight. June 15 is still without civil night at Harstad.

May night by night

The moon runs its cycle as usual, new on May 6 and full on May 20, but with no civil night it makes no difference at Harstad in May.

1
22% lit
no night
2
14% lit
no night
3
8% lit
no night
4
3% lit
no night
5
1% lit
no night
6
0% lit
no night
New
7
3% lit
no night
8
8% lit
no night
9
16% lit
no night
10
25% lit
no night
11
36% lit
no night
12
47% lit
no night
13
58% lit
no night
14
69% lit
no night
15
79% lit
no night
16
87% lit
no night
17
93% lit
no night
18
97% lit
no night
19
100% lit
no night
20
100% lit
no night
Full
21
98% lit
no night
22
94% lit
no night
23
89% lit
no night
24
82% lit
no night
25
74% lit
no night
26
66% lit
no night
27
57% lit
no night
28
47% lit
no night
29
37% lit
no night
30
28% lit
no night
31
19% lit
no night

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

Quiet activity already puts the oval edge over Harstad, so storm days matter more: 97 of the 930 May days from 1996 to 2025 (10%) reached Kp 5, 6th of 12 months. Harstad sits at 67.1 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 0.

May across Norway

Harstad ranks 16th in Norway for civil night on May 15, behind Kristiansand at 5.1 hours. Coming from April (5.3 hours at Harstad), May loses darkness, and June holds about the same.

Civil night on May 15 and May cloud, month-page towns in Norway
Town	Civil night	Cloud
Kristiansand	5.1 h	69%
Stavanger	4.8 h	71%
Haugesund	4.7 h	70%
Oslo	4.5 h	68%
Drammen	4.5 h	68%
Bergen	4.3 h	71%
Hamar	4.1 h	70%
Gjøvik	4.1 h	70%
Lillehammer	3.9 h	75%
Ålesund	3.1 h	82%
Molde	2.9 h	82%
Kristiansund	2.6 h	74%
Harstad	0.0 h	80%

Darkness and moon, every night

Harstad, May 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
Sat May 1	0 min	0 min	0 min	0 min	22%
Sun May 2	0 min	0 min	0 min	0 min	14%
Mon May 3	0 min	0 min	0 min	0 min	8%
Tue May 4	0 min	0 min	0 min	0 min	3%
Wed May 5	0 min	0 min	0 min	0 min	1%
Thu May 6	0 min	0 min	0 min	0 min	0%
Fri May 7	0 min	0 min	0 min	0 min	3%
Sat May 8	0 min	0 min	0 min	0 min	8%
Sun May 9	0 min	0 min	0 min	0 min	16%
Mon May 10	0 min	0 min	0 min	0 min	25%
Tue May 11	0 min	0 min	0 min	0 min	36%
Wed May 12	0 min	0 min	0 min	0 min	47%
Thu May 13	0 min	0 min	0 min	0 min	58%
Fri May 14	0 min	0 min	0 min	0 min	69%
Sat May 15	0 min	0 min	0 min	0 min	79%
Sun May 16	0 min	0 min	0 min	0 min	87%
Mon May 17	0 min	0 min	0 min	0 min	93%
Tue May 18	0 min	0 min	0 min	0 min	97%
Wed May 19	0 min	0 min	0 min	0 min	100%
Thu May 20	0 min	0 min	0 min	0 min	100%
Fri May 21	0 min	0 min	0 min	0 min	98%
Sat May 22	0 min	0 min	0 min	0 min	94%
Sun May 23	0 min	0 min	0 min	0 min	89%
Mon May 24	0 min	0 min	0 min	0 min	82%
Tue May 25	0 min	0 min	0 min	0 min	74%
Wed May 26	0 min	0 min	0 min	0 min	66%
Thu May 27	0 min	0 min	0 min	0 min	57%
Fri May 28	0 min	0 min	0 min	0 min	47%
Sat May 29	0 min	0 min	0 min	0 min	37%
Sun May 30	0 min	0 min	0 min	0 min	28%
Mon May 31	0 min	0 min	0 min	0 min	19%

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

Questions

Can you see the northern lights in Harstad in May?: Not in May 2027. The sun stays above -6 degrees every night at Harstad, so there is no civil darkness.
How dark is Harstad in May?: Harstad averages 0.0 hours of civil night a night in May 2027, from 0 min on the 1st to 0 min on the last night.
How cloudy is Harstad in May?: NASA POWER's 2001 to 2020 climatology gives Harstad's 1 degree cell 80% mean cloud in May, against 81% for the whole year. It is an all-hours average, not a forecast.
What is the best night in May 2027 for aurora in Harstad?: No night in May 2027 has moon-free darkness inside 10 PM to 2 AM at Harstad.
Is May or June better in Harstad?: By civil night times the clear share, May scores 0.0 hours at Harstad and June 0.0. They are level.

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.