Pennsylvania

Solstice, full moon mark summer's official arrival

FILE - In this June 21, 2015, file photo, the sun rises as thousands of revelers gathered at the ancient stone circle Stonehenge to celebrate the Summer Solstice, the longest day of the year, near Salisbury, England. The solstice occurs Monday, June 21, 2016, at 6:34 p.m. on the U.S. East Coast. (AP Photo/Tim Ireland, File)

FILE - In this June 21, 2015, file photo, the sun rises as thousands of revelers gathered at the ancient stone circle Stonehenge to celebrate the Summer Solstice, the longest day of the year, near Salisbury, England. The solstice occurs Monday, June 21, 2016, at 6:34 p.m. on the U.S. East Coast. (AP Photo/Tim Ireland, File)  (The Associated Press)

The summer solstice marks the season's official arrival around the globe Monday.

In the United States, summer begins at 6:34 p.m. on the East Coast. That's when the Sun reaches its highest point in Earth's sky.

Monday also marks the longest period of daylight of the year. The days will get shorter beginning Tuesday until Dec. 21, the winter solstice.

Sky watchers will later be treated to a rare full moon coinciding with the solstice. June's full moon has traditionally been nicknamed the honey moon or the strawberry moon because of its large, reddish-amber appearance in the sky.