Why the Easter moon is pink - Katherine Roberts

I've always been a bit confused by Easter. Why does the date keep moving so that some years it falls at the end of March, and other years (such as this year) it's almost at the end of April? Surely the crucifixion happened on a certain date? Well, apparently that's still in contention, but it seems there are two possible accepted dates of Friday April 7th AD30, or Friday April 3rd AD 33. Good Friday commemorates the day that Jesus died on the cross, and Christians celebrate his resurrection two days later on Easter Sunday. So why isn't Easter always celebrated in the first week of April to coincide with the crucifixion?

Turns out that's the moon's fault.

Easter falls on the Sunday following the first full moon after the spring equinox. It's simple when you know how. The equinox - "equal night" in Latin - is when day and night are the same length, and in the northern hemisphere the spring equinox falls on or around March 21st (sometimes as early as March 19th, but for the Easter calculation most churches use 21st every year). This means Easter Sunday can fall as early as March 22nd, or as late as April 25th (March 21st, plus a lunar month of 28 days, plus a week of 7 days to allow for all possible combinations).

Lunar eclipse by Alfredo Garcia, CC BY-SA 2.0
This year, the first full moon following the equinox occurred two days ago, on Good Friday, and is known as the Pink Moon (although it does not really appear pink). It's named after a spring-flowering North American wildflower, and is also sometimes known as the Sprouting Grass Moon, the Egg Moon (Easter eggs maybe?), or the Fish Moon. The next full moon is called the Flower Moon, and apparently we have the Native Americans to thank for these names. For the full list, see https://www.farmersalmanac.com/full-moon-names.

Being a fantasy author, I love these romantic moon names - and sometimes the moon actually does change colour in the sky.

When the moon is low in the sky near the horizon, it appears yellow or orange because the light must pass through more of the earth's atmosphere, rather like the rising or setting sun. And during a lunar eclipse, which happens when the earth casts a shadow on the moon, it can appear blood red as in the picture.

I used this blood moon in my historical fantasy novel about Genghis Khan's rise to power, which I linked to the Mongolian 'Red Circle Day' - an important festival in Genghis Khan's time, according to the Secret History of the Mongols. How often this festival took place is not certain, but the red moon seemed an appropriate symbol for my book - and a crimson moon against the Khan's black war banner made a striking cover.

The Legend of Genghis Khan

"Once in a Blue Moon" is a well known saying meaning "very rarely", and a modern definition claims the Blue Moon is a second full moon in the same month, which occurs once every 32 months, i.e. approximately once every three years. Sometimes, however, the moon really does appear blue when there is a lot of smoke in the sky, such as from a major volcanic eruption, and this is likely where the saying originally came from.

Do you know of any other moon names? Or seen any other moon colours? Feel free to add them to the comments below.

Meanwhile, Happy Easter!

Katherine Roberts writes fantasy and historical fiction for young readers. For more details of her books visit www.katherineroberts.co.uk


The moon was especially gorgeous this year as viewed from the island of Itaparica in Brazil. Thanks for this lovely post!
Sounds lovely, Dipika! What colour was it?
This reminded me of a poem we read at school - I think the original ballad must have been in Scots as it's about the shipwreck that caused the Scottish throne to be fought over in the 13th century. I've looked it up to make sure it was the poem I thought it was (The Ballad of Sir Patrick Spens). Apparently seeing this kind of moon meant stormy weather ahead:

"I saw the new moon late yestreen
With the old moon in her arm;
And if we go to sea, master,
I fear we'll come to harm."
I know that ballad, Cecilia! Can't remember all the words, but think I must have heard a version by either Fairport Convention or Steeleye Span. (I can still hear part of the tune in my head). Yes, the moon is connected to a lot of folklore, and not only when it's full.
Katherine, it looked deep orange, almost a shade of red. Was competing with the sun :)
Umberto Tosi said…
It's commonplace, but always amazes me that we each look at the same moon, and see it in different colors and dimensions depending on where we are - perhaps thousands of miles apart - and what time of night it is. I do my best to run outside to gaze at full moons, blood moons, lunar eclipses and all other special moons, weather permitting. And I never fail to feel the magic of it first hand - magic that you've evoked in your writing as well. Thanks for the poetic post, Katherine!

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