The summer solstice occurs exactly when the Earth's and the moon's axial tilt is most inclined towards the sun, at its maximum of 23° 26'. Though the summer solstice is an instant in time, the term is also colloquially used like Midsummer to refer to the day on which it occurs. Except in the polar regions (where daylight is continuous for many months), the day on which the summer solstice occurs is the day of the year with the longest period of daylight. The summer solstice occurs in June in the Northern Hemisphere north of the Tropic of Cancer (23°26'N) and in December in the Southern Hemisphere south of the Tropic of Capricorn (23°26'S. The Sun reaches its highest position in the sky on the day of the summer solstice. However, between the Tropic of Cancer and the Tropic of Capricorn, the highest sun position does not occur at the summer solstice, since the sun reaches the zenith here and it does so at different times of the year depending on the latitude of the observer. Depending on the shift of the calendar, the summer solstice occurs some time between December 21 and December 22 each year in the Southern Hemisphere, and between June 20 and June 21 in the Northern Hemisphere.