Today is Summer Solstice (also known as Litha). People around the world have observed spiritual and religious seasonal days of celebration during the month of June. Most have been religious holy days which are linked in some way to the summer solstice. On this day, typically June 21, the daytime hours are at a maximum in the Northern hemisphere, and night time is at a minimum. It is officially the first day of summer. It is also referred to as Midsummer because it is roughly the middle of the growing season throughout much of Europe.
"Solstice" is derived from two words: "sol" meaning sun, and "sistere," to cause to stand still. This is because, as the summer solstice approaches, the noonday sun rises higher and higher in the sky on each successive day. On the day of the solstice, it rises an imperceptible amount, compared to the day before. In this sense, it "stands still."
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, or within a day or two of, June 21 -- the first day of summer. The lowest elevation occurs about December 21 and is the winter solstice -- the first day of winter, when the night time hours reach their maximum.