2024 has a lot of supermoons! There are five new supermoons, and four full supermoons in 2024. So … what’s a supermoon?
New moon happens when the moon (in its monthly orbit of Earth) goes more or less between the sun and Earth. Full moon happens when the moon (in its monthly orbit) is on the opposite side of Earth from the sun. And perigee – from the root words peri meaning near and geo meaning Earth – is the moon’s closest point to Earth in a month.
So the new or full moon closely coincides with perigee several times each year. When that happens, in the language of popular culture, we have a supermoon.
Supermoons came from popular culture
As it’s used today, the word supermoon was coined by astrologer Richard Nolle in 1979. And according to Nolle’s definition, a full moon or new moon is a supermoon when it’s also within 90% of its closest point to Earth. However, different websites calculate supermoons differently. EarthSky uses supermoon dates as determined by astronomer Fred Espenak. He’s best known for his time at the Goddard Space Flight Center, where he became a world expert on eclipse predictions. Additionally, his method of calculating supermoons takes into account changes in the moon’s orbit during each lunar cycle.
New supermoons in 2024
Fred Espenak’s new supermoon table gives us these values – dates and moon distances – for new supermoons in 2024. Contrast these moon distances to the average moon distance of 238,900 miles (384,472 km).
Note dates are based on UTC time so some supermoons may fall on the previous date your local time.
Jan 11: 226,927 miles (365,204 kilometers)
Feb 09: 222,913 miles (358,744 kilometers)
Mar 10: 221,767 miles (356,899 kilometers)
Apr 08: 223,575 miles (359,809 kilometers)
May 08: 227,881 miles (366,739 kilometers)
The new supermoon of March 10, 2024, will be the closest new supermoon for 2024.
And the new supermoon of April 8, 2024, will be the moon that blocks out the sun causing a total solar eclipse on April 8, 2024.
Full supermoons in 2024
Fred Espenak’s full supermoon table gives us these values – dates and moon distances – for full supermoons in 2024. Contrast these moon distances to the average moon distance of 238,900 miles (384,472 km).
Note: Fred’s dates are based on UTC time, so some supermoons may fall on the previous date your local time.
Aug 19: 224,917 miles (361,969 kilometers)
Sep 18: 222,131 miles (357,485 kilometers)
Oct 17: 222,055 miles (357,363 kilometers)
Nov 15: 224,853 miles (361,866 kilometers)
And the full supermoon of September 18, 2024, will be a Super Harvest Moon plus have a partial lunar eclipse.
Then the full supermoon of October 17, 2024, will be a Super Hunter’s Moon and the closest full supermoon for 2024.
Supermoon hype?
Some astronomers complain about the name supermoon. They like to call supermoons hype. But supermoons aren’t hype. They’re special. Many people now know and use the word supermoon. In fact, we even notice some diehards are starting to use it now. Such is the power of folklore.
The hype aspect of supermoons probably stemmed from an erroneous impression people had when the word supermoon came into popular usage … maybe a few decades ago? Some people mistakenly believed a full supermoon would look much, much bigger to the eye. But it doesn’t. Nowadays, most people seem to realize that supermoons don’t look bigger to the eye than ordinary full moons.
It’s true experienced observers do say they can detect a difference. But you’d have to be a very keen observer to notice it. Truly, most of us can’t tell any difference in the size of a supermoon and an ordinary full moon.
Is a supermoon brighter?
But … do supermoons look brighter than ordinary full moons? Yes! By a noticeable amount. That’s because a supermoon exceeds the disk size of an average-sized moon by up to 8% and the brightness of an average-sized full moon by some 15%. And then, it exceeds the disk size of a micro-moon (a year’s most distant and therefore smallest full moon) up to 14% and the brightness of a micro-moon by some 30%. So go outside on the night of a full supermoon. Even if you’re a casual observer of the moon, there’s the potential you’ll notice the supermoon is exceptionally bright!
For a visual reference, the size difference between a supermoon and micro-moon is proportionally similar to that of a U.S. quarter versus a U.S. nickel. Again, that difference isn’t noticeable to the eye at the moon’s distance. But the brightness difference is noticeable.
By the way, before we called them supermoons, we in astronomy called these moons perigean full moons, orperigean new moons. No doubt about it, supermoon is catchier.
High tides from new and full supermoons
What’s more, all supermoons have the potential to cause higher-than-usual tides. High tides during the full or new moon are called spring tides. High tides during a full or new moon at perigee are called perigean spring tides, or, sometimes, king tides. And nowadays you sometimes hear them called supermoon tides.
These perigean or king or supermoon spring tides tend to follow the date of new or full moon by a day or so. These especially high tides are highly dependent on the shapes of local coastlines and on local weather conditions.
Do extra-high supermoon tides cause flooding? Maybe yes and maybe no. Flooding typically occurs when a strong weather system accompanies an especially high spring tide. According to Fred Espenak, the gravity from the closest supermoon is only 4% greater than the gravity from the moon at its average distance.
How often do we have a supermoon?
Often! But it also depends on your definition of supermoon.
Here’s a list of each year’s closest full supermoon perigees from 2016 to 2026 (from Espenak’s full supermoon table):
November 14, 2016 (356,523 kilometers or 221,533 miles)
December 3, 2017 (357,987 kilometers or 222,443 miles)
January 2, 2018 (356,604 kilometers or 221,583 miles)
February 19, 2019 (356,846 kilometers or 221,734 miles)
April 8, 2020 (357,035 kilometers or 221,851 miles)
May 26, 2021 (357,462 kilometers or 222,117 miles)
July 13, 2022 (357,418 kilometers or 222,089 miles)
August 31, 2023 (357,344 kilometers or 222,043 miles)
October 17, 2024 (357,364 kilometers or 222,056 miles)
November 5, 2025 (356,980 kilometers or 221,817 miles)
December 24, 2026 (356,740 kilometers or 221,668 miles)
The recurring cycle of supermoons
The closest full moon supermoon in 2024 will recur after 14 lunar months (14 returns to full moon) after the closest full supermoon of 2023. That’s because 14 returns to full moon almost exactly equal 15 returns to perigee, a period of about one year, one month, and 18 days.
The mean lunar month (full moon to full moon, or new moon to new moon) = 29.53059 days, whereas the mean anomalistic month (perigee to perigee, or apogee to apogee) = 27.55455 days. Hence:
14 lunar months (14 returns to full moon) x 29.53059 days = 413.428 days
15 anomalistic months (15 returns to lunar perigee) x 27.55455 days = 413.318 days
So given that closest supermoon recurs in cycles of 413 days (about one year, one month and 18 days), we can expect the closest full moon supermoon to come about one month and 18 days later next year. Thus, the closest full supermoon of 2023 – August 31 – will be followed by the closest full supermoon 14 months later – October 17 – in 2024. The closest full supermoon of 2025 will be November 5, 2025.
Bottom line: In 2024, there are five new supermoons in a row from January to May. And there are four full supermoons in a row from August to November. The closest full supermoon will be October 17.
Read more: Does a supermoon have a super effect on us?
Want to see 2023’s brightest supermoon? Photos here
