Vernal Equinox Oddities: Lots to Learn about the First Day of Spring

By Bob Berman at Almanac.com.

March Equinox Fun Facts

On this March equinox, does the Sun rise due east and set due west? Are day and night of equal duration? Some of these answers are quite contrary to common wisdom. Bob Berman brings the fun facts to celebrate the first day of spring!

On the vernal equinox (March 19, 2024), the Sun will cross the celestial equator—an imaginary line in the sky above Earth’s equator—from south to north. This instant marks the March equinox everywhere on Earth. If you live in the Northern Hemisphere, it’s the spring equinox; in the Southern Hemisphere, it’s the autumn equinox.

Why Does the Spring Equinox Fall on Different Dates?

If you thought that the Spring Equinox only ever occurred on March 21, you may be dating yourself.

Spring arrived on the 21st of March during most of the 20th century, but the event slides earlier and earlier during the 400-year Gregorian calendar cycle. The final March 21 equinox was in 2007—even if we use Greenwich Time, as many almanacs do.

Now, the 21st is gone for the rest of our lives, unless you believe in reincarnation and want to check back in during the 22nd century.

Are Day and Night Equal at the Equinox?

The word equinox is derived from two Latin words—aequus (equal) and nox (night). The equinox is famously the time of balance, with theoretically 12 hours of sunshine and 12 hours of non-Sun.

In practice, they are not exactly equal. There’s actually more day than night on the day of an equinox. Why?

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