Summertime!

The seasons of the year are caused by the 23.5º tilt of the earth's axis. Because the earth is rotating like a top or gyroscope, the North Pole points in a fixed direction continuously -- towards a point in space near the North Star. But the earth is also revolving around the sun. During half of the year, the southern hemisphere is more exposed to the sun than is the northern hemisphere. During the rest of the year, the reverse is true. At noontime in the Northern Hemisphere the sun appears high in the sky during summertime, and low during winter. The time of the year when the sun reaches its maximum elevation occurs on the summer solstice - the day with the greatest number of daylight hours. It typically occurs on June 21st - the first day of summer.