Tropic of Cancer

Tropic of Cancer, imaginary line of latitude showing the northernmost point on the earth at which the sun can appear directly overhead. The sun's rays shine straight down on the Tropic of Cancer on June 20 or 21, which is the summer solstice and the first day of summer in the Northern Hemisphere. Lying 23°27' north of the equator and encircling the earth, the Tropic of Cancer also represents the northern boundary of the Tropical Zone.

See also: Latitude; Tropics.