Full Moon on the Spring Equinox

A supermoon on the first day of spring!

March 19, 2019
Moonflowers

Rate this Post: 

Average: 4.7 (487 votes)

This is one of those rare years when the full Moon lands right smack on the spring equinox—on March 20, 2019, in North America. This only happens three times a century, on average. Plus, it’s the third and final “supermoon.” Enjoy the extra-bright equinox full moon Wednesday night!

It’s an event with wide appeal because the Moon is the only night sky object recognized by everyone in the world, while the equinox is one of the few remaining sky-based events still found on all calendars.

  • For most people, the equinox’s main significance is that it’s the start of spring, so to be exact, you can wave flags and pour extra treats into the bird feeders at 5:58 PM EDT Wednesday afternoon, March 20.
  • It’s also the day when the Sun rises and sets precisely due east and due west. So on Wednesday you can rotate and calibrate your sundial, that job you’ve been putting off for so long.
  • It’s the day when the Sun moves across the sky in a laser-straight line. It’s when the noonday sun stands in its medium or average height above your southern horizon.
  • And, yes, the days and nights are sort of equal for people throughout the world. Not exactly equal, but close enough.

Full Moon on the Vernal Equinox

The Full Moon of March happens just a tad less than four hours after the equinox, at 9:43 PM EDT on March 20 2019, so it will indeed appear perfectly round Wednesday night.

This is the closest coincidence of the vernal equinox and full moon since March 20, 2000. For the Northern Hemisphere, this March full moon ushers in the first full moon of the spring season; in the Southern Hemisphere, this is the first full moon of autumn.

Further, this is the third and final “supermoon” of 2019—which is just a catchy term for a full moon closely coinciding with perigee, the moon’s closest point to Earth in its monthly orbit.

moonrisemk_connelley_1600_full_width.jpg
Moonrise at Sunset Through Mauna Kea’s Shadow. Image: Michael Connelley (U. Hawaii)

Moonrise and Sunset Coincide!

The equinox and full Moon are a close enough match that you can look for moonrise at very nearly the same moment as sunset!  Both of our major sky lights hovering opposite each other—the sun setting just as the full moon is rising.

Very cool, and yet their opposition is not perfectly precise. The Sun will do its job and set at the true west spot on your horizon. You’ll be able to ascertain how your home is oriented to the cardinal directions. But the Moon’s orbit is tilted five degrees from the Sun-Earth plane, so the trio of celestial bodies is rarely aligned in all three dimensions, which is why total solar eclipses are so uncommon.

On Wednesday evening, at the time of moonrise, the Moon will be four degrees north of the ecliptic plane, which will make it come up a whopping eight full moon diameters to the left of due east.

Yet, if you want the Moon to guide your eyes to true east, it’s doable. But you must wait 40 minutes after moonrise, as the Moon slowly glides up and to the right. Then it will hover precisely due east. We can’t give you an exact time because we don’t know where you live. But roughly speaking, when you see the Moon just a few degrees above the horizon that evening, it’ll be hovering true east.

And that’s the full Moon equinox story. We’re out of room, which is why we neglected eggs balancing on edge, squirrels speaking French, and all the other supposed effects you find on the Web. But you can find more spring equinox facts and folklore here.

Did You Know: Without the full Moon on the equinox, Easter 2019 would have been in March. See more about Easter 2019.

About This Blog

Welcome to “This Week’s Amazing Sky,” the Almanac’s hub for everything stargazing and astronomy. Bob Berman, longtime and famous astronomer for The Old Farmer’s Almanac, will help bring alive the wonders of our universe. From the beautiful stars and planets to magical auroras and eclipses, he covers everything under the Sun (and Moon)! Bob, the world’s mostly widely read astronomer, also has a new weekly podcast, Astounding Universe