The midnight sun is a phenomenon which occurs for varying lengths of time between the spring and autumn equinoxes in areas between the Polar Circles and the Poles. The definition of the midnight sun is that the sun should not sink below the horizon, and therefore be visible 24 hours a day, as long as clouds or geographical landmarks do not obscure it.
In Longyearbyen, the midnight sun period is from around April 20 to August 23. Many people connect the midnight sun with summer, but during the first few weeks of midnight sun it is still full winter on Svalbard, allowing for fantastic experiences with skis, dog sleds or snowmobiles around the clock. We have tours starting as late as 10:00 pm, so that you can get the most out of your Svalbard experience.
The closer you are to the Pole, the longer the midnight sun period lasts. At the North Pole, it is possible to see this phenomenon from March 18 to September 25.
Those areas with the longest period of midnight sun in the summer, also experience a dark period in the winter. Due to the twilight effect, as light refracts in the atmosphere, this dark period is not necessarily 100% dark, 24 hours a day. This is the same reason it is light even before the sunrise.