In the northern hemisphere, the longest day of the year when the Sun is farthest north. In the southern hemisphere, winter and summer solstices are exchanged. 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
With little or no Moon to interfere with the show, this is a GREAT year for watching the Perseid meteor shower. Hooray! These meteors are leftovers from Swift-Tuttle comet and are a favorite among many skywatchers. The shower can be visible from July 17th through August 24th, and will peak overnight on August 12th at 60 sightings per hour. The Perseids tend to strengthen in number as late night deepens into midnight, and typically produce the most meteors in the wee hours before dawn.