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First Day of Spring 2015: Vernal Equinox
Spring begins with the vernal equinox at 7:02 A.M. (EDT) on March 20, 2015 in the Northern
Hemisphere. Here’s more about the start of spring, signs of spring, and stunning spring photos!
The Vernal Equinox
Ah, spring! This season brings increasing daylight, warming temperatures, and the rebirth of
flora and fauna.
The word equinox is derived from the Latin words meaning “equal night.” Days and nights are
approximately equal everywhere and the Sun rises and sets due east and west.
At the equinoxes, the tilt of Earth relative to the Sun is zero, which means that Earth’s axis
neither points toward nor away from the Sun. (However, the tilt of Earth relative to its plane of
orbit, called the ecliptic plane, is always about 23.5 degrees.)
Vernal Equinox Questions and Answers
Question: Why doesn’t the vernal equinox (equal night) on March 20 have the same number of
hours for day and night?
Answer: Our former astronomer, George Greenstein, had this to say: "There are two reasons.
First, light rays from the Sun are bent by the Earth's atmosphere. (This is why the Sun appears
squashed when it sets.) They are bent in such a way that we are actually able to see the Sun
before it rises and after it sets. The second reason is that 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 was
to shrink to a star like point and we lived in a world without air, the spring and fall equinoxes
would truly have ‘equal nights.’”
Question: According to folklore, you can stand a raw egg on its end on the equinox. Is this true?
Answer: 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. Try this
yourself and let us know what happens!
Signs of Spring
Spring is also the time when worms begin to emerge from the earth, ladybugs land on screen
doors, green buds appear, birds chirp, and flowers begin to bloom. The vernal, or spring, equinox
signals the beginning of nature’s renewal in the Northern Hemisphere.
You can track when the seasons change by recording animal behaviors and the way that the
plants grow. Listen to the new sounds and observe what you hear and see.