Happy first day of Spring! Facts about the Vernal Equinox

Happy first day of Spring! Facts about the Vernal Equinox

Spring has sprung! Well, not really in Chicago, where it is presently snowing. Technically speaking, though, today is the first day of spring because it is the vernal equinox in this hemisphere.

What is the vernal equinox?

It is the day on which  the sun is directly over the equator. After today, the sun’s direct rays then shift into the Northern Hemisphere for the next six months.  That will happen on Thursday, March 20th at at 12:57 p.m. EDT.

Does it fall on the same day each year?

No, the vernal equinox moves. It was on March 20th last year and this year, but it can also occur on March 21st.


The date varies due to a calendar problem. The Gregorian calendar has 365 days per year, but it actually takes our planet a little longer to orbit the sun. That little extra 0.256 days to go around the sun is what throws off the vernal equinox from one specific date, according to the Huffington Post.

What does the word “equinox” mean?

The word “equinox” comes from the Latin words aequus (equal) and nox (night) according to almanac.com. Day and night are both approximately 12 hours each on an equinox.

What does “vernal” mean?


Is it spring everywhere?

Our friends in Australia and other parts of the Southern Hemisphere are marking the first day of autumn today. There’s actually a movement to start calling this event the March Equinox or Northward Equinox to “avoid North Hemisphere bias.” because it is only spring in the Northern Hemisphere.

Are night and day the same length on the vernal equinox?

Image from The Weather Channel

Image from The Weather Channel

It depends on who you ask. “During the equinox, both day and night are balanced to nearly 12 hours each all over the world,” says the Weather Channel. However, the exact equality between day and night takes place just before the vernal equinox, according to the National Geographic.

Do the days get longer?

Thank goodness, yes, they do for those of us in the Northern Hemisphere. In the Southern Hemisphere, however, they get shorter.

Does this have anything to do with Easter?

The Vernal Equinox determines the date of Easter for Catholics and other Christians. The date of Easter is the first Sunday after the first full moon after the Vernal Equinox.

Is this the same start date as meteorological spring?

It is not. Meterological spring begins on March 1, a month when average temperatures increase by 10 degrees over the month.

Did the ancients know about this spring equinox thing?chichenitza

They did.  The great Sphinx points toward the rising sun on the date of the Spring Equinox.

At Chichen Itza, Mexico, the Mayans celebrated the spring equinox with “The Return of the Sun Serpent.” The setting sun creates a triangular shadow on the El Castillo pyramid. It creates an illusion that looks like a descending snake that’s said to be the feather serpent god Kukulkan.

This is the date you can balance an egg on its end, right?

I’ve done it, and it was very cool. Apparently, my efforts had everything to do with a bumpy egg and nothing to do with the tilt of the planet. The International Business Times says, “This is an age-old myth that does not hold any truth. Trying to balance an oval-shaped object on its end is no easier on the spring equinox than on any other day. There is no scientific way the Earth’s axis could help stabilize the egg.” Bummer.

But do not despair – the days are getting longer and warmer and this snow will have to eventually melt and today is just the start of an amazing Spring, right? Please say yes. I can’t take more winter.

Read about the Summer Solstice here or check out Facts about the Autumnal Equinox.

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