The June or Summer Solstice is the first day of the Season of Summer. On or about this date the Sun is farthest north and the length of time between sunrise and sunset in the northern hemisphere is the longest of the year.

Although June 21 is generally considered to be the date of the June Solstice, the precise time can vary and fall between June 20 and June 22 (although the latter is very rare).

The Sun has been climbing in the sky and on this day it stops directly over the Tropic of Cancer (solstice means "standing still sun"). The hours of sunlight have been getting longer and longer each day, but after this date they will start getting shorter.

As the Earth circles around the Sun, it leans about 23° on its axis like a spinning top frozen in an off-kilter position. At this time, the entire Arctic area is continually exposed to sunlight even though the Earth is rotating.

Although the actual North Pole has had continuous sunlight for over three months by now, today everywhere above the Arctic Circle has 24 hours of sunlight.

This day is also the first day of the Season of Winter in the southern hemisphere, and there, the length of time between sunrise and sunset is the shortest of the year. While the Arctic has continuous sunlight, Antarctica is likewise in the dark.