Cue the warmer temperatures, rain showers and blooming flowers–spring is almost here!
Meteorological spring always begins on March 1 and runs through May 30. It’s a three-month season which makes it helpful for analyzing data and seasonal trends.
You're probably more familiar with the “first day of spring” that shows up on the calendar. It's also known as astronomical spring, March equinox, spring equinox or the vernal equinox. So, does spring always begin on the same calendar date and at the same time?
The beginning of spring varies year to year. Spring begins on March 19, 20 or 21. Why the variation in dates? Believe it or not, it has to do with the Earth's revolution around the sun.
The Earth takes about 365.25 days to complete a revolution around the sun. A normal year has 365 days. That extra quarter of a day (about six hours) is part of the reason the vernal equinox fluctuates by about six hours every year.
Fun fact: The extra quarter of a day is also why we have a leap year every four years.
Until 2048, the March equinox will happen on March 19 every leap year. In between the leap years, the March equinox will occur on March 20.
What about March 21? Time zones outside of the United States have had a March 21 equinox this century. However, the U.S. mainland won’t have a vernal equinox on March 21 at all in the 21st century!
Spring 2022 runs from March 20 until June 20. Summer begins on June 21, 2022. Enjoy this transitional season before the heat and humidity move in for an extended stay!