In 2007, summer begins June 21, 2:06 P.M. EDT (18:06 UT)

Solstice, comes from the Latin for sun stands still. In astronomy: either of the two points on the ecliptic that lie midway between the equinoxes (separated from them by an angular distance of 90°).
At the solstices the sun's apparent position on the celestial sphere reaches its greatest distance above or below the celestial equator,