Whether the sun sets in Greenland depends entirely on the time of year and your specific location. Greenland is the world’s largest island, with a significant portion lying within the Arctic Circle. This geographical placement causes extreme variations in the light cycle, leading to periods where the sun either never sets or never rises.
The Basic Answer: Latitude and the Arctic Circle
The extreme light cycles experienced in Greenland are a direct consequence of the Earth’s axial tilt, which is approximately 23.5 degrees relative to its orbital plane around the sun. This consistent tilt means that during the summer months in the Northern Hemisphere, the North Pole is angled toward the sun. Conversely, during the winter, the North Pole is tilted away from the sun.
The dividing line for this phenomenon is the Arctic Circle, located at about 66°33′ North latitude. Any location substantially north of this line experiences periods of continuous daylight or continuous darkness. The Earth’s 24-hour rotation is not enough to carry these northern regions into shadow during their respective summer or out of shadow during their winter. This mechanism causes the sun to remain above or below the horizon for extended periods, creating the Arctic’s unique seasonal light patterns.
The Phenomenon of the Midnight Sun
The Midnight Sun refers to the period during summer when the sun remains visible above the horizon for a full 24 hours. In the northern regions of Greenland, this continuous daylight typically occurs from late May to late July, though the exact duration is dependent on latitude. For example, a town like Ilulissat experiences the Midnight Sun from early June to mid-July, while further north in Qaanaaq, the sun does not set for approximately three and a half months.
During this time, the sun does not climb high into the sky but instead appears to circle the horizon, bathing the landscape in warm, continuous hues of pink, red, and gold. This experience is often described as a perpetual twilight rather than intense midday light. The endless daylight allows for round-the-clock activities, essentially blurring the line between day and night.
The Phenomenon of the Polar Night
The Polar Night is the opposite phenomenon, occurring during the winter when the sun remains below the horizon for more than 24 hours. In the northernmost parts of Greenland, such as Qaanaaq, the sun disappears below the horizon from late October until mid-February. This does not mean the region is plunged into pitch-black darkness for months.
Instead, the Polar Night is characterized by prolonged periods of twilight around midday. The period of civil twilight, where there is enough light for outdoor activities because the sun is less than six degrees below the horizon, provides a few hours of illumination. Only at the most extreme northern latitudes does the sun dip far enough below the horizon to cause astronomical darkness, where refracted sunlight is no longer visible. The return of the sun after the Polar Night is often a celebrated event in Arctic communities.
Geographic Differences in Light Cycles
Greenland’s immense size means that the light phenomena vary significantly from north to south. The most extreme light cycles, the longest periods of Midnight Sun and Polar Night, are experienced in the far north, at latitudes like Qaanaaq. The length of both periods shortens dramatically as one moves southward.
The capital city of Nuuk, and other southern communities like Qaqortoq, are located south of the Arctic Circle. These areas experience a normal cycle of sunrise and sunset every day of the year. While they do not have a Midnight Sun, their proximity to the Arctic means they still have extremely long summer days with bright nights where the sun barely dips below the horizon, and very short winter days with only a few hours of daylight.