Daylight hours in Longyearbyen
Longyearbyen gets 24h 00m of daylight on its longest day in May, and 0h 00m on its shortest in January — a difference of 24h 00m across the year.
How fast the days change
Around 16 April, Longyearbyen gains or loses about 36.2 minutes of daylight every day.
That is quick enough to notice week to week, which is why spring seems to arrive all at once this far from the equator.
Sunrise and sunset by month
On the 15th of each month, in Arctic/Longyearbyen local time, daylight saving included.
| Month | Sunrise | Sunset | Daylight | Solar noon |
|---|---|---|---|---|
| January | the sun does not rise | 0h 00m | 12:06 | |
| February | 11:57 | 12:25 | 0h 27m | 12:11 |
| March | 06:29 | 17:43 | 11h 14m | 12:06 |
| April | 02:38 | 23:16 | 20h 38m | 12:57 |
| May | the sun does not set | 24h 00m | 12:53 | |
| June | the sun does not set | 24h 00m | 12:57 | |
| July | the sun does not set | 24h 00m | 13:03 | |
| August | the sun does not set | 24h 00m | 13:01 | |
| September | 05:38 | 20:06 | 14h 28m | 12:52 |
| October | 09:26 | 16:00 | 6h 34m | 12:43 |
| November | the sun does not rise | 0h 00m | 11:41 | |
| December | the sun does not rise | 0h 00m | 11:52 | |
Solstices and equinoxes
| Date | Sunrise | Sunset | Daylight | |
|---|---|---|---|---|
| March equinox | 20 Mar | 05:49 | 18:20 | 12h 30m |
| June solstice | 21 Jun | no sunset | 24h 00m | |
| September equinox | 22 Sep | 06:29 | 19:10 | 12h 42m |
| December solstice | 21 Dec | no sunrise | 0h 00m | |
The equinoxes give almost exactly twelve hours of daylight everywhere on earth — "almost" because sunrise is defined by the sun's upper edge rather than its centre, and the atmosphere bends its light over the horizon before it has really arrived. Both lengthen the day by a few minutes.
Assumptions
- Sea-level horizon. Hills, mountains and buildings all delay sunrise and bring sunset forward, sometimes by a lot in a valley.
- Standard refraction. Sunrise is taken at −0.833°, allowing for the sun's disc and average atmospheric bending. Unusual air conditions shift it by a minute or two.
- Local clock time, with daylight saving applied from the IANA timezone database.