Spring officially begins with the Spring Equinox on Tuesday, March 20, 2018. This event marks the astronomical first day of spring in the Northern Hemisphere.
Equinoxes and solstices are opposite on either side of the equator, and the March equinox is also known as the “spring (vernal) equinox” in the Northern Hemisphere and as the “autumnal (fall) equinox” in the Southern Hemisphere.
WHAT IS AN EQUINOX?
An equinox is the moment in which the plane of Earth’s equator passes through the center of the Sun’s disk, which occurs twice each year, around 20 March and 23 September. On an equinox, day and night are of approximately equal duration all over the planet.
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.)
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.
SIGNS OF THE EQUINOX IN NATURE
The vernal equinox signals the beginning of nature’s renewal in the Northern Hemisphere!
- Worms begin to emerge from the earth. In fact, the March Full 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 is what triggers birds to sing? 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.