what is the day length at the north pole in summer
Daytime Near the poles, which coincide with the rotational axis of the Earth as it passes through the surface, the seasonal variations in the length of daytime are extreme. In fact, within 23.5째 latitude of the poles, there will be at least some days each year during which the sun never goes below the horizon. There will also be days when the sun never rises above the horizon. This number will be fewer, but close to the number of days in the summer where the sun doesn't set (for example the sunrise is usually a few days before the spring equinox and extends a few days past the fall equinox). This phenomenon of more daylight than night is not unique to the poles. In fact, at any given time slightly more than half of the earth is in daylight. The 24 hours of summer daylight is known as the midnight sun that is famous in some northern countries. To the north, the Arctic Circle marks this 23.5째 boundary. To the south, the Antarctic Circle marks the boundary. These boundaries correspond to 66.5째 north or south latitude, respectively. Because the Sun's disc itself is about half a degree in diameter and is very bright, truly dark days during which the sun never seems to rise are only seen beyond 72째 north or south latitude.
Antarctic Circle Directly on the Antarctic Circle these events occur, in principle, exactly once per year: at the December and June solstices, respectively. However, because of atmospheric refraction and mirages, and because the sun appears as a disk and not a point, part of the midnight sun may be seen on the night of the southern summer solstice up to about 50 minutes (′) (90 km (56 mi)) north of the Antarctic Circle; similarly, on the day of the southern winter solstice, part of the sun may be seen up to about 50′ south of the Antarctic Circle. That is true at sea level; those limits increase with elevation above sea level, although in mountainous regions there is often no direct view of the true horizon. Mirages on the Antarctic continent tend to be even more spectacular than in Arctic regions, creating, for example, a series of apparent sunsets and sunrises while in reality the sun remains under the horizon.