Calculator · NOAA solar equations
Midnight sun and polar night calculator
Choose an Arctic place and a date: the sun's day, and the whole year.
Pick a place and a date
Longyearbyen · 21 June 2027
24h
Midnight sun: the sun does not set
Same date in London: sun up 16 h 39 min.
Chosen place
Longyearbyen
78°13′N 015°38′E
Midnight sun
Up at solar midnight
Sunrise
Up at solar midnight
Sunset
0h
Dark (sun below −12°)
Compared with
London
51°30′N 000°08′W
Sunrise and sunset
04:43
Sunrise
21:22
Sunset
3h17min
Dark (sun below −12°)
- Sun up
- Civil twilight
- Nautical twilight
- Dark
Every value, to the minute
Chosen place
Longyearbyen
78°13′N 015°38′E
- Sunrise
- Up at solar midnight
- Sunset
- Up at solar midnight
- Daylight (sun up)
- 24 h
- Daylight + civil twilight
- 24 h
- Dark (sun below −12°)
- 0 h
- Sun at solar noon
- 35.2°above the horizon at 12:59
- Sun at solar midnight
- 11.7°above the horizon at 00:59 (next day)
Local times · Arctic/Longyearbyen · UTC+2
Compared with
London
51°30′N 000°08′W
- Sunrise
- 04:43
- Sunset
- 21:22
- Daylight (sun up)
- 16 h 39 min
- Daylight + civil twilight
- 18 h 14 min
- Dark (sun below −12°)
- 3 h 17 min
- Sun at solar noon
- 61.9°above the horizon at 13:02
- Sun at solar midnight
- −15.1°below the horizon at 01:02 (next day)
Local times · Europe/London · UTC+1
The whole year at Longyearbyen, 2027
- Daylight (sun up)
- + civil twilight
- London, daylight
- Midnight sun
- Polar night
- Chosen date
112days
Polar night
from 27 October 2026 to 15 February 2027
127days
Midnight sun
from 19 April to 23 August 2027
112days
Polar night
from 27 October 2027 to 15 February 2028
Month by month, as a table
| Date | DaylightLongyearbyen | + civil twilightLongyearbyen | DaylightLondon |
|---|---|---|---|
| 1 Jan 2027 | 0 h | 0 h | 7.8 h |
| 1 Feb 2027 | 0 h | 2.7 h | 9.2 h |
| 1 Mar 2027 | 7.5 h | 11.2 h | 10.8 h |
| 1 Apr 2027 | 15.7 h | 20.5 h | 12.8 h |
| 1 May 2027 | 24 h | 24 h | 14.8 h |
| 1 Jun 2027 | 24 h | 24 h | 16.2 h |
| 1 Jul 2027 | 24 h | 24 h | 16.5 h |
| 1 Aug 2027 | 24 h | 24 h | 15.5 h |
| 1 Sep 2027 | 18.7 h | 24 h | 13.5 h |
| 1 Oct 2027 | 10.5 h | 13.8 h | 11.5 h |
| 1 Nov 2027 | 0 h | 6 h | 9.7 h |
| 1 Dec 2027 | 0 h | 0 h | 8.2 h |
Computed at sea level with the NOAA solar equations (sun's centre at −0.833°); mountains shorten the visible sun by days.
Why the light matters on a voyage
Up here the sun, not the clock, sets the rhythm. Figures for 2027.
11.7°
sun at midnight, 21 June 2027
No night in a Svalbard summer
More
At Longyearbyen the sun stays up around the clock from 19 April to 23 August 2027. At solar midnight on 21 June 2027 it still stands 11.7° above the northern horizon. In June and July there is no sunset at all.
03:00
the sun is still up
Sleep by the clock
More
With the sun up at 3 a.m., your body loses its cue for night. Bring an eye mask, keep regular hours for sleep, and go to bed by the clock, not by the light.
02:00
watch, in full daylight
Night watches in daylight
More
On an open-sea passage, like Tromsø to Longyearbyen, someone keeps watch around the clock, as the collision regulations require. Under the midnight sun the 2 a.m. watch is in full daylight: easier to spot whales, seabirds and drifting ice, and easy to lose track of the day.
14 August 2027
first dark midnight, Tromsø
Darkness returns in August
More
In Tromsø the sun first sinks more than 6° below the horizon at midnight on the night of 14 August 2027, and more than 12° on the night of 1 September 2027. From then on a clear night can be dark enough to see the northern lights when they are out, and by 30 September 2027 Tromsø has 8.3 h with the sun below −12°.
4.4h
of twilight, 21 Dec 2027
Polar night is not pitch black
More
Tromsø's polar night runs from 28 November 2027 to 14 January 2028, yet on 21 December 2027 there are still 4.4 h of civil twilight around noon: a soft blue light, then a long night for the aurora.
How the calculator works
The same definitions as every light figure on this site.
How it works
- Sun up
- The sun's centre above −0.833°: its upper edge clears a sea-level horizon, with standard refraction.
- Sun's altitude
- The geometric angle of the sun's centre above or below the horizon, without refraction. Between 0° and −0.833° the sun still shows, grazing the horizon.
- Midnight sun
- The sun stays up for the whole solar day, from one solar midnight to the next.
- Polar night
- The sun's centre stays below −0.833° even at solar noon.
- Civil twilight
- The sun less than 6° below the horizon: light enough for most things outdoors.
- Dark
- The sun more than 12° below the horizon: nautical twilight is over and the horizon fades from view at sea. Astronomers wait for −18°.
- Solar noon and midnight
- The moments the sun is highest and lowest. They depend on the longitude, the time zone and the date, not on 12:00 on the clock.
- Times
- Local clock time in each place's IANA time zone, summer time included.
The year view is computed in 10-minute steps; the cards above are to the minute.
Other almanacs can differ by a minute or two: they round differently, use another refraction or correct for the observer's height.
Planning to sail up here?
Cap II's 2027 season sails from Tromsø: Svalbard in June–July, northern lights and whales in winter 2027–28. All dates are provisional.