<P> The tropics occupy a band of the Earth's surface between 23.5 ° north latitude and 23.5 ° south latitude . Within this band, the Sun will pass almost directly overhead on at least one day per year . The line of 23.5 ° north latitude is called the Tropic of Cancer, because when it was named, the Sun passed overhead at this location at the time of year when it was within the zodiac sign of Cancer . The equivalent line of south latitude is called the Tropic of Capricorn, for similar reasons . If they had been named today using the constellation in which the sun is currently in at the time it is directly overhead the tropic line, they would have been called, respectively, the Tropics of Gemini and Sagittarius . The sun enters and leaves each sign of the zodiac slightly later each year at the rate of about 1 day every 72 years . For more information, see precession of the equinoxes . </P> <P> On the Tropical Circles, the Sun is directly overhead only once per year, on the corresponding solstice . At latitudes closer to the Equator and on the Equator itself, it will be overhead twice per year (on the equinoxes in the case of the Equator). Outside the tropics, the Sun never passes directly overhead . </P> <P> 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 23.5 ° 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 23.5 ° boundary . To the south, the Antarctic Circle marks the boundary . These boundaries correspond to 66.5 ° 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 72 ° north or south latitude . </P> <P> At and near the poles, the sun never rises very far above the horizon, even in summer, which is one of reasons why these regions of the world are consistently cold in all seasons (others include the effect of albedo, the relative increased reflection of solar radiation of snow and ice). Even at the summer solstice, when the sun reaches its highest point above the horizon at noon, it is still only 23.5 ° above the horizon at the poles . Additionally, as one approaches the poles the apparent path of the Sun through the sky each day diverges increasingly from the vertical . As summer approaches, the Sun rises and sets become more northerly in the north and more southerly in the south . At the poles, the path of the Sun is indeed a circle, which is roughly equidistant above the horizon for the entire duration of the daytime period on any given day . The circle gradually sinks below the horizon as winter approaches, and gradually rises above it as summer approaches . At the poles, apparent sunrise and sunset may last for several days . </P>

What is the day length at the north pole in summer
find me the text answering this question