The Midnight Sun is a natural event where the sun remains visible for a continuous period of 24 hours or more during the local summer. This phenomenon erases the traditional cycle of day and night, resulting in perpetual daylight at high latitudes. This article explores the cities that host this extended daylight and the scientific reason for its occurrence.
The Scientific Explanation for Constant Daylight
The presence of continuous summer daylight is a direct consequence of the Earth’s 23.5-degree axial tilt. As the planet orbits the sun, this tilt causes one hemisphere to be angled toward the sun during its summer season. When the Northern Hemisphere is tilted toward the sun, the North Pole and surrounding regions are perpetually exposed to sunlight as the Earth rotates.
The geographical boundary for this event is the Arctic Circle, an imaginary line of latitude at 66.5 degrees North. Any location at or above this line experiences at least one 24-hour period where the sun does not dip below the horizon around the summer solstice. The further north a location is situated beyond this circle, the longer the period of continuous daylight lasts.
Cities Where the Midnight Sun Occurs
The core regions that experience the Midnight Sun are spread across the northernmost parts of Europe, North America, and Russia. In Norway, the city of Tromsø (69.6°N) sees continuous daylight from late May to late July. Even further north, the settlement of Longyearbyen in Svalbard experiences the sun remaining above the horizon for more than four months straight.
Across the Atlantic, the northernmost city in the United States, Utqiagvik (formerly Barrow), Alaska, enjoys 82 to 85 consecutive days of sunlight each summer. In Canada, towns like Inuvik in the Northwest Territories experience 24-hour sunlight for over 50 days each season, while Iqaluit celebrates extended daylight around the summer solstice. Russia’s Murmansk, a major port city well above the Arctic Circle, is a location for this phenomenon. Even cities just south of the Arctic Circle, like Reykjavik, experience near-continuous daylight with a bright twilight due to atmospheric light refraction.
The Winter Contrast: Polar Night
The same high-latitude locations that enjoy the Midnight Sun in summer experience the opposite phenomenon in winter, known as the Polar Night. This occurs when the polar region is angled away from the sun, preventing the sun from rising above the horizon for more than 24 hours. This period of prolonged darkness intensifies the closer a location is to the North Pole, lasting for weeks or months.
The term “night” is often misleading, as true pitch blackness is rare outside the highest latitudes. Instead, many areas experience a persistent “polar twilight,” where scattered sunlight illuminates the sky enough for a muted glow during the middle of the day. For instance, Utqiagvik, Alaska, endures a polar night lasting over two months, while the northern Swedish town of Kiruna experiences 28 days of this continuous dark period.