Spring is nearly here; the vernal equinox, signaling the official onset of the season in the Northern Hemisphere, arrives on Tuesday, March 19th.
In 2024, the spring equinox will happen precisely at 11:06 p.m. EDT on Tuesday. But what’s the significance of this day as the beginning of spring, and why is it applicable only to the Northern Hemisphere?
What exactly constitutes an equinox?
The year experiences only two equinoxes: the vernal and autumnal equinoxes. These events occur when the sun is directly overhead at noon, resulting in nearly equal durations of day and night within a 24-hour period. The term “equinox” originates from the Latin words “aequus” and “nox,” meaning “equal night.”
Typically falling on March 19, 20, or 21, a spring equinox on March 21 is considered rare, as noted by the Farmer’s Almanac. In fact, such an occurrence has not transpired in the mainland United States throughout the entire 21st century, and the next one is not anticipated until 2101.
The variability in the date of the equinox is partly attributed to Earth’s orbit around the sun, which spans 365.24 days, while a calendar year consists of 365 days, as explained by the National Centers for Environmental Information.
How does the spring equinox differ from meteorological spring?
Although the vernal equinox in 2024 occurs on March 19, meteorological spring commenced at the beginning of the month. NASA distinguishes between two types of seasons: meteorological and astronomical.
Meteorological seasons are aligned with the calendar and correspond to the yearly temperature cycle. They are divided into three-month periods. Meteorological spring spans from March 1 to May 31 each year.
On the other hand, astronomical seasons are determined by Earth’s axial tilt and its position in orbit around the sun.
When does spring commence in the Southern Hemisphere?
In the Southern Hemisphere, spring begins in September, coinciding with the onset of fall in the Northern Hemisphere.
During the March equinox, the Southern Hemisphere experiences later sunrises, earlier sunsets, cooler winds, and the shedding of dry leaves. Conversely, in the Northern Hemisphere, this equinox brings earlier sunrises, later sunsets, gentler winds, and the emergence of new plant growth.
Customs, practices, and legends
While Easter isn’t until the end of March, there’s a tradition involving eggs associated with the equinox. According to a post on weather.gov, Chinese tradition suggests that an egg can be balanced on its end at the precise moment when winter transitions to spring. However, in reality, it’s technically feasible to balance an egg on its end on any day of the year, provided one has a considerable amount of patience.
Nowruz, the Iranian or Persian New Year, coincides with the spring equinox. Celebrated for over 3,000 years, Nowruz festivities extend across the Balkans, the Black Sea Basin, the Caucasus, Central Asia, the Middle East, and various other regions, as noted by the United Nations.
When will the upcoming solstice and equinox occur?
Those eagerly awaiting the arrival of summer must hold out until the summer solstice on Thursday, June 20. Following that, the autumnal equinox, marking the onset of fall, will take place on Sunday, Sept. 22. Finally, the winter solstice is set for Saturday, Dec. 21, later in the year.