Midnight Sun

• Details
• Geography

The midnight sun is a natural phenomenon that occurs in the summer months in places north of the Arctic Circle or south of the Antarctic Circle, when the Sun remains visible at the local midnight. When the midnight sun is seen in the Arctic, the Sun appears to move from left to right, but in Antarctica the equivalent apparent motion is from right to left. This occurs at latitudes from 65°44' to 90° north or south, and does not stop exactly at the Arctic Circle or the Antarctic Circle, due to refraction.

The opposite phenomenon, polar night, occurs in winter, when the Sun stays below the horizon throughout the day.

Around the summer solstice (approximately 21 June in the Northern Hemisphere and 21 December in the Southern Hemisphere), in certain areas the Sun does not set below the horizon within a 24-hour period.

Because there are no permanent human settlements south of the Antarctic Circle, apart from research stations, the countries and territories whose populations experience the midnight sun are limited to those crossed by polar circles: the Canadian Yukon, Nunavut, and Northwest Territories; the nations of Iceland, Finland, Norway, Sweden, Denmark (Greenland), Russia; and the state of Alaska in the United States.

The largest city of the world north of the Arctic Circle, Murmansk (Russia), experiences the midnight sun from 22 May to 22 July (62 days).

A quarter of Finland's territory lies north of the Arctic Circle, and at the country's northernmost point the Sun does not set at all for 72 days during summer.

In Svalbard, Norway, the northernmost inhabited region of Europe, there is no sunset from approximately 19 April to 23 August. The extreme sites are the poles, where the Sun can be continuously visible for half the year. The North Pole has midnight sun for 6 months from late March to late September.

Because of atmospheric refraction, and also because the Sun is a disc rather than a point, the midnight sun may be experienced at latitudes slightly south of the Arctic Circle or north of the Antarctic Circle, though not exceeding one degree (depending on local conditions). For example, Iceland is known for its midnight sun, even though most of it (Grímsey is the exception) is slightly south of the Arctic Circle. For the same reasons, the period of sunlight at the poles is slightly longer than six months. Even the northern extremities of the United Kingdom (and places at similar latitudes, such as St. Petersburg) experience twilight throughout the night in the northern sky at around the summer solstice.

Places sufficiently close to the poles, such as Alert, Nunavut, experience times where it does not get entirely dark at night yet the Sun does not rise either, combining effects of the midnight sun and polar night, for example where during the "day" it reaches civil twilight and at "night" only reaches astronomical twilight.

Locations where the Sun remains less than 6 (or 7) degrees below the horizon – between 60° 34’ (or 59° 34’) latitude and the polar circle – experience midnight civil twilight instead of midnight sun, so that daytime activities, such as reading, are still possible without artificial light on a clear night.

White Nights have become a common symbol of Saint Petersburg, Russia, where they occur from about 11 June to 2 July,[2] and the last 10 days of June are celebrated with cultural events known as the White Nights Festival.

The northernmost tip of Antarctica also experiences white nights near the Southern Hemisphere summer solstice.

Learn about White Night festivals.

See what happened in 2021 in St Petersburg.