Everyone is eager to get back to warm weather, so find out when spring starts—and enjoy vernal equinox facts and folklore.
Specifically, the Northern Hemisphere marks the spring equinox on Monday, March 20, 2017, at exactly 6:29 A.M. EDT.
Watch the video below for a re-play or our live show, “Celebrating the March Equinox.” We share observatory views, courtesy of Slooh, plus interesting equinox facts and spring folklore.
When Does Spring Begin?
Astronomically speaking, the equinox (March 19 or 20 every year) marks spring’s beginning in the Northern Hemisphere (whereas it announces fall’s arrival in the Southern Hemisphere). The equinox happens at the same moment worldwide, even if our clock times reflect a different time zone.
Meteorologically speaking, in the Northern Hemisphere, the official spring season always begins on March 1 and continues through May 31. Summer begins on June 1; autumn, September 1; and winter, December 1.
- Weather scientists divide the year into quarters this way to make it easier to compare seasonal and monthly statistics from one year to the next. The meteorological seasons are based on annual temperature cycles rather than on the position of Earth in relation to the Sun, and they more closely follow the Gregorian calendar. Using the dates of the astronomical equinoxes and solstices for the seasons would present a statistical problem because these dates can vary slightly each year.
What is an Equinox?
At the Vernal Equinox, the Sun crosses the celestial equator on its way north along the ecliptic.
All over the world, days and nights are approximately equal. The name equinox comes from Latin words which mean “equal night”—aequus (equal) and nox (night).
- Enjoy the increasing sunlight hours, with earlier dawns and later sunsets. See your personalized Sun rise and set calculator.
On the equinox, Earth’s two hemispheres are receiving the Sun’s rays about equally because the tilt of the Earth is zero relative to the Sun, which means that Earth’s axis neither points toward nor away from the Sun. (Note, however, that the Earth never orbits upright, but is always tilted on its axis by about 23.5 degrees.)
- Enjoy our page on the reason for the seasons.
Scientific explanation aside, our ancestors were more connected to the Sun than we are today. They observed its pathway across the sky; they tracked how the sunrise, sunset, and daylength changed, using the Sun (and Moon) as a clock and calendar. If you have ever been to Stonehenge or Machu Picchu, you’ll see examples of ancient seasonal markers.
Question: Are Day and Night Truly Equal on the Equinox?
Answer: Nope, day and night are not exactly equal at the equinox for two reasons. First, daytime begins the moment any part of the Sun is over the horizon, and it is not over until the last part of the Sun has set. If the Sun were to shrink to a starlike point and we lived in a world without air, the spring and fall equinoxes would truly have ‘equal nights.’
Signs of the Equinox in Nature
- Worms begin to emerge from the earth. Even the March Moon is called “The Full Worm Moon” for this reason.
- Notice the arc of the Sun across the sky as it shifts toward the north. Birds are migrating northward, along with the path of the Sun.
- Speaking of birds, did you know that the increasing sunlight triggers bird song? Cool, eh? Enjoy our Bird Songs page.
- Trees, shrubs and flowers are sensitive to temperature and daylength, too! Since ancient days, people have used them as indicators of when the weather is right for planting. For example: Blooming crocus are your cue to plant radishes, parsnips and spinach. See more of nature’s signs.
- Of course, the longer days bring warmer weather! Both we and the animals around us strip off our clothes and heavy coats!
- Ready, set, plant! March is time to start gardens and sow seeds in many regions. See your personalized Best Planting Dates.
Question: According to folklore, you can stand a raw egg on its end on the equinox. Is this true?
Answer: Folklore or not, this egg trick sounded like a bit of fun to us. One spring, a few minutes before the vernal equinox, several Almanac editors tried this trick. For a full workday, 17 out of 24 eggs stood standing. Three days later, we tried this trick again and found similar results. Perhaps 3 days after the equinox was still too near. Perhaps the equinox has nothing to do with it. Perhaps we just don’t like to take ourselves too seriously! Try this yourself and let us know what happens.
One swallow does not make a spring.
Bluebirds are a sign of spring; warm weather and gentle south breezes they bring.
In spring, no one thinks of the snow that fell last year.
Don’t say that spring has come until you can put your foot on nine daisies.
The whole Earth smiles, thy coming to greet.
Look around! Observe! What are the signs of spring in your region? Please share below!
More seasonal pages: