When is the sun directly overhead?
Only in the tropics, on one or two days a year: the dates and times for sixteen cities.
Definitions
Midnight sun and polar night
The midnight sun is when the sun does not set at all for a whole day; the polar night is when it does not rise. Both happen inside the polar circles, at 66.56° north and south, because the Earth’s axis is tilted 23.44° from the perpendicular to its orbit.
The figures here use the same definitions as sunrise and sunset everywhere else: the sun is up while the top of its disc is above the horizon, with the usual 34 arcminutes of atmospheric refraction. Those two details, the sun’s 16-arcminute radius and the refraction, add up to 0.83°, enough to give Rovaniemi a month of midnight sun although it lies 6 km south of the Arctic Circle.
The dates
How long the sun stays up, and away
| Place | Latitude | Midnight sun | Polar night | Day length range |
|---|---|---|---|---|
| Longyearbyen, Svalbard | 78.2° N | 19 Apr – 24 Aug (128 days) | 27 Oct – about 14 Feb | 0 – 24 h |
| Utqiaġvik, Alaska | 71.3° N | 11 May – 1 Aug (83 days) | 19 Nov – about 21 Jan | 0 – 24 h |
| Tromsø, Norway | 69.6° N | 18 May – 25 Jul (69 days) | 28 Nov – about 14 Jan | 0 – 24 h |
| Murmansk, Russia | 69.0° N | 21 May – 22 Jul (63 days) | 2 Dec – about 10 Jan | 0 – 24 h |
| Kiruna, Sweden | 67.9° N | 27 May – 16 Jul (51 days) | 11 Dec – about 1 Jan | 0 – 24 h |
| Rovaniemi, Finland | 66.5° N | 6 Jun – 6 Jul (31 days) | none | 2.2 – 24 h |
| Fairbanks, Alaska | 64.8° N | none | none | 3.7 – 21.8 h |
| Reykjavik, Iceland | 64.1° N | none | none | 4.1 – 21.1 h |
| McMurdo Station, Antarctica | 77.8° S | 24 Oct – 20 Feb (about 120 days) | 26 Apr – 19 Aug (116 days) | 0 – 24 h |
Two rules of thumb fall out of the table. The midnight sun season grows by more than a month over the first three degrees north of the circle, then more slowly. And the polar night is always shorter than the midnight sun at the same latitude, by three weeks at Tromsø: refraction lifts the sun over the horizon early and holds it there late, which lengthens summer and shortens winter.
What it looks like
Polar night is not pitch darkness
In Tromsø on 21 December the sun stays 3.1° below the horizon at noon, so there is civil twilight from about 09:30 to 13:50, several hours of soft blue light with a pink glow to the south. Further north the light fades: in Longyearbyen the noon sun is 11.7° down at the solstice, and midday brings only a little nautical twilight. For two months in midwinter there is barely any daylight at all.
At midsummer the opposite happens. In Tromsø the sun at midnight stands 3.1° above the northern horizon, and around 60° north, in St Petersburg, Helsinki or Oslo, it dips only about 6.5° below it, so the sky never gets fully dark: the white nights.
Antarctica
The southern polar regions
The Antarctic Circle has no towns, only research stations. The seasons are reversed: at McMurdo Station the sun stays up from late October to late February and stays down from late April to late August. The southern midnight sun is a few days shorter than the northern one at the same latitude: the Earth is closest to the sun in early January and moves fastest then, so the half-year from the September equinox to the March one, the southern summer, is about a week shorter than the northern summer.
The sun position map shows the day length and the sun’s path for any place on any date, and the winter solstice page lists how long the shortest day lasts across the world. For the equally strange tropics, see when the sun is directly overhead.
Keep reading
Related articles
How long does golden hour last?
From under half an hour on the equator to two hours in the north: golden hour by latitude and season.
Where does the sun rise? Sunrise and sunset direction through the year
Due east only near the equinoxes: in London the sunrise point swings 80° along the horizon.