It most frequently occurs on June 21, the day we consider to be the first day of summer. But because the Earth’s rotation doesn’t perfectly align with our 24-hour calendar — this was a Leap ...

The 2024 summer solstice arrives June 20 at 4:51 p.m. Eastern time, according to the U.S. Naval Observatory. A day later, on June 21, the full ... the Gregorian calendar introduced a special ...