Greenland, the world’s largest island, is situated predominantly within the Arctic Circle, which dictates an extreme annual cycle of light and dark. Whether the sun sets in Greenland depends entirely on the specific time of year and the location on the island. Sometimes the sun does not set for months, and at other times, it does not rise for a similar duration. This unique relationship with daylight is governed by astronomical mechanics, creating two distinct seasonal phenomena: the Midnight Sun and the Polar Night.
The Midnight Sun: Constant Daylight
The Midnight Sun is the natural phenomenon where the sun remains visible above the horizon for 24 hours or longer. This period of perpetual daylight occurs during the summer months in the polar regions, peaking around the Summer Solstice in late June. The Earth’s axial tilt of approximately 23.4 degrees is the fundamental reason for this continuous light. As the planet orbits the sun, this tilt causes the region inside the Arctic Circle to be continuously exposed to solar radiation as the Earth rotates.
For locations well north of the Arctic Circle, the sun follows a circular path in the sky, dipping lowest around midnight but never fully disappearing. This constant light alters the traditional perception of time. Many accommodations use blackout curtains to help people maintain a regular sleep schedule, and the extended daylight hours allow activities like sailing and hiking to continue long into the conventional night.
The Polar Night: Constant Darkness
The Polar Night is the opposite phenomenon, defined by a period when the sun does not rise above the horizon for 24 hours or more. This occurs during the winter months, specifically around the Winter Solstice in December, when the polar region is tilted away from the sun. The sun remains below the horizon for this entire duration, plunging the region into a period of extreme darkness.
However, the term “Polar Night” does not always mean absolute, pitch-black darkness. Much of the area experiences civil twilight, where the sun is only a few degrees below the horizon. During civil twilight, scattered sunlight illuminates the sky around noon, creating a faint, deep blue glow that prevents true darkness. Only the most extreme northern latitudes experience the deepest forms of Polar Night, where the sky remains nearly black.
Latitude Matters: Differences Across Greenland
Greenland spans a vast range of latitudes, from about 59°N to 84°N, meaning the experience of light and dark varies dramatically from south to north. Only the areas that lie entirely above the Arctic Circle (approximately 66.5°N) experience the true 24-hour Midnight Sun and Polar Night. The duration of these extremes increases significantly the farther north one travels.
For instance, the far northern town of Qaanaaq experiences continuous daylight for about three and a half months in the summer. Conversely, Qaanaaq has a Polar Night lasting nearly four months in the winter, from late October to mid-February. These northern communities face the most prolonged periods of continuous light and dark.
In contrast, southern locations, such as the capital city of Nuuk, lie below the Arctic Circle and experience a sunset every day of the year. While the sun always sets in Nuuk, daylight hours are severely restricted in winter, dropping to as little as four to six hours around December. Even in the southernmost towns, summer nights are exceptionally bright, with up to 20 hours of daylight, creating a bright twilight that feels like continuous day.