Summer Solstice

In the northern hemisphere, the longest day of the year when the Sun is farthest north. In the southern hemisphere, this would be your winter solstice, marking the shortest day of the year. The summer solstice marks the first day of the season of summer. The declination of the Sun on the (northern) summer solstice is known as the tropic of cancer (23° 27′).

http://scienceworld.wolfram.com/astronomy/SummerSolstice.html