Official Start to Summer: Longest Day of Sunshine

The summer solstice, which falls on June 21, occurs when the tilt of the Earth is closest to the sun. The sun is directly over the Tropic of Cancer, 23.5 degrees north latitude on this day.

The sun appears to be high in elevation for a few days before, during and after the solstice due to the sun reaching its farthest northern point along the path it travels.

Since the sun is positioned farthest north and high in the sky on June 21, it is the longest day of the year, providing the most hours of sunlight, according to AccuWeather.com Senior Meteorologist Tom Kines.

The changing of seasons can be thought of as solstices and equinoxes. A solstice refers to when the sun has reached the farthest northern or southern position along its rotation. On June 21, it will be the farthest north, and on Dec. 21, it will be the farthest south. An equinox is when the sun is directly over the equator, Kines said.

Changes in seasons can be attributed to the tilt of the Earth's axis and the rotation of the sun. The solstices and equinoxes occur when the tilt of the Earth changes as it makes a rotation around the sun. As the Earth moves along this path, the angles shift resulting in the changing seasons. A common misconception is that the distance the sun is from Earth changes the seasons, but in reality it is the angle of the Earth in relation to the sun.

The other solstices and equinoxes include the autumnal equinox on Sept. 23, the winter solstice on Dec. 21 and the vernal equinox on March 21, better known as the start of spring.

Story by AccuWeather.com Staff Writer Molly Cochran

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Washington, D.C. (1870)
President Grant signed a measure establishing a Federal meteorological service; later assigned to Signal Corps, U.S. Army. Riverside Ranger Station 1933 -66 deg., U.S. record for Feb. (48 states). Yellowstone Park

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