If you are an astronomer, today marks the official start of astronomical summer (for climatologists, it started on June 1).  The sun reaches its northernmost point in the sky at 12:39 PM EDT.  You can read about the solstice at https://www.timeanddate.com/calendar/june-solstice.html.

EarthSky also has a nice gallery of photos taken at Stonehenge in England, where the stones align according to astronomical dates (link).

Today is the longest day of the year–go out and enjoy it!

june-solstice-illustration

Source: Andrew Dunn, Commons Wikimedia
Source: Andrew Dunn, Commons Wikimedia