For those eager for summer warmth, this week will be special: the earliest summer solstice in more than two centuries is scheduled to occur on Thursday afternoon.
Specifically, this will be the earliest summer solstice since June 20, 1796, when George Washington was president and the Union had only 16 states.
The early arrival of the summer solstice is due to a complex relationship between the Earth’s annual orbit around the Sun, its daily rotation, and the way we mark the solstice on our calendars.
When is the summer solstice?
The summer solstice is the exact moment each year when the sun is at its highest point in the sky, which occurs at 4:50 p.m. on a Thursday. It marks the start of astronomical summer in the Northern Hemisphere.
At that moment, the sun is directly above the Tropic of Cancer, the northernmost point where the sun moves across the sky, and so days close to the summer solstice have the most hours of daylight of the year.
Some people call this the “longest day,” but technically it is the day with the most daylight, with 24 hours in a day. The hours of daylight remain consistent for a few more days until the winter solstice in late December, but then start to decrease day by day.
The reason Earth has solstices, equinoxes and seasons is because the Earth’s axis is tilted as a result of a chance collision with another object billions of years ago.
Is summer here already?
Many parts of the country have been experiencing summer-like weather for the past few weeks, which is why meteorologists refer to the hottest three months of the year (June, July, and August) as summer.
But the real heat is yet to come: Climatologists say that on average, there’s a one-month lag between the summer solstice and the highest summer temperatures. Brian BrettschneiderThis is why July is often the hottest month of the year in many areas.
The summer solstice comes about three weeks after the start of meteorological summer, which began on June 1st.
Who celebrates the summer solstice?
Around the world, many people celebrate the summer solstice with music and festivals. In Britain, on the first day of summer, hundreds of people visit the ancient site of Stonehenge, where the annual summer solstice observation has been held for thousands of years.
The rock formations at Stonehenge are perfectly aligned with the movement of the sun during both the summer and winter solstices. Although their origin and reasons for formation are unknown, Stonehenge is one of the most popular places to observe the summer solstice.
According to Scientific American, the Mayans and Aztecs also used the summer and winter solstices to mark their days, building structures that were precisely aligned with the shadows cast by the sun.
Keep in mind that Thursday is also the winter solstice in the Southern Hemisphere, which means winter arrives for the roughly 12% of the world’s population that lives there.
