In 2022, the June solstice occurs on Tuesday, June 21, marking the astronomical first day of summer, which means it’s the shortest day of the year. Discover interesting facts and legends about the summer solstice!
The Summer Solstice occurs in June
The June solstice (also known as the summer solstice) occurs in the Northern Hemisphere when the Sun travels along its northernmost journey in the sky. In the northern hemisphere, this is the astronomical start of summer. (The June solstice marks the astronomical start of winter in the Southern Hemisphere when the Sun is at its lowest position in the sky.)
On Tuesday, June 21, 2022, at 5:14 a.m. EDT, the June solstice will occur. The summer solstice occurs when Earth reaches the point in its orbit where the North Pole is at its greatest tilt (approximately 23.5 degrees) toward the Sun, resulting in the longest day and shortest night of the calendar year in the Northern Hemisphere. (By “longest day,” we mean the duration of time during which the sun is visible.) The Northern Hemisphere receives sunlight at its highest direct angle of the year on the day of the June solstice.
The June solstice marks the start of winter in the Southern Hemisphere.
What Is the Summer Solstice?
The June solstice (also known as the summer solstice) happens when the Sun reaches its highest and northernmost positions in the sky in the Northern Hemisphere. In the northern hemisphere, it is the start of summer. (In the Southern Hemisphere, the June solstice occurs when the Sun reaches its lowest position in the sky, signalling the start of winter.)
The word “solstice” is derived from the Latin solstitium (Sun + stitium) (still or stopped). The Sun does not rise and set at the same spots on the horizon each morning and evening due to Earth’s tilted axis; its rise and set positions in the sky change northward or southward as Earth moves around the Sun during the year.
Throughout the year, the Sun’s path in the sky changes, either higher or lower. The June solstice is notable because it is at this time that the Sun reaches its northernmost position in the sky, where its path remains unchanged for a brief period of time. The Sun appears to turn around after the solstice and proceed in the other direction. The apparent path of the Sun as seen in the sky at the same time each day, for example, at local noon, is the motion referred to here. Its journey produces an analemma, a flattened figure eight, over the course of a year. The Sun, of course, is not moving (unless you count its own orbit around the Milky Way galaxy); rather, the tilt of Earth’s axis as it orbits the Sun, as well as Earth’s elliptical, rather than circular, orbit, produce the shift in position in the sky that we on Earth see.
Does the Solstice Always Occur on the Same Day?
The June solstice is determined by when the Sun reaches its northernmost point from the celestial equator, not by a precise calendar day or time. As a result, the solstice does not always fall on the same day. It now occurs on June 20, 21, and 22. The Summer Solstice is the day when the sun shines for the longest duration of time. At the solstice, the Sun is at its highest point in the sky; its rays impact Earth at a more direct angle, generating the efficient warming we call summer. Because the Sun is at its highest point in the sky on this day, your shadow (at local, or solar, noon, not clock-time noon) will be the shortest of the year. [Local noon is defined as the time when the Sun crosses the local meridian (an imaginary line connecting the North and South poles) and is at its highest point in the sky for the day.]
This is the shortest day of the year in the Southern Hemisphere, and it heralds the start of winter.
Why Doesn’t the Summer Solstice Fall on the Same Date Each Year?
In the Northern Hemisphere, the summer solstice occurs between June 20 and 22. This is due to the gap between the Gregorian calendar system, which has 365 days, and the tropical year (the time it takes for Earth to circle the Sun once), which has 365.242199 days. The Gregorian calendar adds a leap day every four years to compensate for the missing fraction of days, which causes the summer date to shift backwards. However, additional factors like the gravitational pull of the Moon and planets, as well as the minor wobble in Earth’s rotation, affect the date.
Why isn’t the Summer Solstice—the longest day of the year—also the hottest day of the year?
The Earth’s atmosphere, land, and seas take some of the Sun’s incoming energy and store it before releasing it as heat at different rates. Water heats (or cools) more slowly than air or land. Due to the angle of sunlight and the length of the day, the Northern Hemisphere receives the greatest energy (maximum intensity) from the Sun at the summer solstice. However, due to spring temperatures, the land and oceans are still relatively chilly, thus the maximum warming effect on air temperature has not yet been seen. The land, particularly the oceans, will eventually release stored heat from the summer solstice back into the atmosphere. Depending on latitude and other factors, the year’s highest temperatures generally arrive around late July, August, or later. This effect is called seasonal temperature lag.
