What on Earth is the Summer Solstice?


June 21st is the summer solstice and is often associated with the beginning of summer.  But what is the summer solstice?  Throughout history, cultures – even ancient ones – have known that the days follow a regular pattern of growing longer and shorter each year.  This is because the earth tilts on its axis.  The summer solstice marks the day with the longest sunshine of the year in areas above the equator.

Leaning Toward the Sun

On June 21, 2019 at 15:54 UTC (11:54 a.m. Eastern time), the north pole will be tilted more toward the sun than it is on any other time of the year.  The summer solstice occurs each year in the northern hemisphere between June 20 and June 22, depending on the year.  This makes the days in the northern hemisphere longer and the nights shorter.  In fact, at this time of the year, all part of the earth in the northern hemisphere have days that are longer than 12 hours.  Meanwhile, all parts of the earth in the southern hemisphere have days shorter than 12 hours.

The opposite phenomenon happens in the southern hemisphere.  The south pole points farthest from the sun than it does on any other day of the year, so the nights are longer and daylight hours are the shortest on that day. 

Of course, the reverse happens at the winter solstice in December. Below is an illumination of the earth view on June 21, 2019 by the U.S. Naval Observatory.

The Start of Summer

Astronomically, the summer solstice marks the beginning of summer because that is when the sun is the highest in the sky.  Many cultures and interested groups (including the Farmer’s Almanac) follow the astronomical calendar.  However, meteorologists divide the year into four seasons based on temperature cycles and consider the beginning of summer to be June 1, and the end to be August 31. 

Solstice Celebrations

Many cultures celebrate the summer solstice.  Stonehenge is the most famous site of celebration of this event.  Around 5,000 years ago, some people placed large stones in a circle in an area of what is now Wiltshire, England.  The stones are aligned perfectly with the summer solstice sunrise.  While little is known about Stonehenge, each year thousands of people travel to Wiltshire to celebrate the summer solstice.

In Sweden, the summer solstice is celebrated on Midsummer’s Day and rivals Christmas Day. The Swedes have many festivities on that day, including eating the first strawberries of the year. The solstice is also celebrated in religious ceremonies.  From Florence to Siena, cathedrals celebrate this day. In fact, the architecture of these amazing edifices is designed with the passage of the sun in mind.  

So, on June 21st, grab some friends and celebrate this ancient, astronomical and mysterious event!