2024’s summer solstice is Earth’s earliest since 1796
On average, the summer solstice occurs on June 21 of most years, as the Earth’s north pole is tilted maximally toward the Sun at a particular moment on that day. As the Earth revolves around the Sun over the course of a year, its axis remains pointed in the same direction, so that the orientation of Earth in space goes through a cycle:
The equinoxes and solstices given here apply to the northern hemisphere; in the southern hemisphere, seasonal equinoxes and solstices are opposed, as seasons are determined by the direction that Earth’s south pole points, rather than the north pole.
But this year, in 2024, the summer solstice will be a little earlier than usual: on June 20 for most of the world. In fact, the time at which the solstice occurs, 20:51 UTC (or 4:51 PM EDT/1:51 PM PDT), marks the earliest summer solstice for planet Earth since the year 1796: when George Washington, the very first President of the United States of America, was still president. There’s a fascinating scientific reason for this, with enormous implications for the rest of the century.
There are many different ways to mark the passage of time, but for our purposes as denizens of Earth, we use precisely none of these as our measure.
