Have you ever tried to balance a raw egg on its end? There’s a legend that says you can only do that successfully on the first day of spring because of the position of the Earth’s axis and a perceived change in gravity. It’s a myth –– you can do it on any day of the year! But it highlights how fascinated we are with the start of spring.
The first day of spring falls on a different day, depending on whether you refer to the astronomical or meteorological spring. According to the meteorological calendar, spring always begins on March 1 and ends on May 31. The start of astronomical spring can fall on March 19, 20, or 21.
The first day of spring is also different for the northern and southern hemispheres. In the southern hemisphere, meteorological spring begins on September 1, and the astronomical spring begins on September 22 or 23 (which is the fall equinox for the northern hemisphere).
The meteorological seasons are easy to follow. Spring (March-May), Summer (June-August), Fall (September-November), and Winter (December-February) are all exactly three months long.
These seasons are based on the annual temperature cycle. They aim to make it easier for meteorologists who observe and forecast the weather and climate to compare seasonal and monthly statistics.
Traditional seasons varied from 89 to 93 days, making it difficult to compare statistics and observe trends from one year to the next and over a set timeframe.
Astronomical Spring starts on the day of the vernal equinox when the Earth’s tilt is zero relative to the Sun, and the Sun passes directly over the equator. During the vernal equinox, the Earth’s axis is neither pointing toward nor away from the Sun. After this point, the Northern Hemisphere tilts toward the Sun.
It’s the point where both northern and southern hemispheres experience approximately equal amounts of daylight (in reality, it’s never the same). After this point, the northern hemisphere starts to see more daylight than darkness. Hours of daylight continue to increase until the summer solstice at the end of June, when the northern hemisphere has the most sun rays in 24 hours. Every planet in our solar system has equinoxes and solstices.
In 2021, astronomical spring begins on Saturday, March 20 at 5:37 a.m. EDT while spring 2022 starts on Sunday, March 20.