This Monday, August 19th, 2024, a full Blue supermoon in the sign of Aquarius will peak at 2:26 p.m. ET.
But what exactly is a Blue Moon, what does it mean, and when can we expect to see one again?
Read on to learn more.
What is a Blue Moon?
Blue Moons fall into one of two categories.
The moon’s cycle is 29.5 days, a hair — or moonbeam — shorter than the average length of a calendar month.
Thus, sometimes a full moon can occur at the beginning of a month, leaving enough time for another later on.
By modern definition, when two full moons fall in a single month, the second full moon is called a Blue Moon, monthly Blue Moon or a calendrical Blue Moon.
A seasonal Blue Moon is defined as the third of four full moons in a single season.
How often do Blue Moons occur?
In astronomical terms, Blue Moons rise fairly regularly, approximately every two to three years.
Fun fact — since there are roughly 29.5 days between full moons and February has only 28 days on average and 29 at best, it will never host a calendrical Blue Moon.
Are Blue Moons ever actually blue?
A Blue Moon isn’t actually blue in color, though on very rare occasions it can appear that way, due to atmospheric conditions created by large-scale forest fires and/or major volcanic eruptions.
In the wake of the eruption of the Indonesian volcano Krakatoa in 1884, a massive cloud of ash and dust was driven 50 miles into the stratosphere.
These ash particles acted as a filter, scattering red light and causing both the moon and sun to appear blue-green.
August Blue Moon
On Monday, August 17th, we’ll experience a seasonal Blue Moon, — the third of four full moons to rise between summer solstice and the fall equinox.
After Monday’s lunation, we will not see another Blue Moon until May 31, 2026, when one will rise and shine in the sign of Sagittarius.
Why is it called a Blue Moon?
The term “blue moon” is commonly attributed to a pair of 16th-century friars who published a scathing pamphlet criticizing the Roman church.
The two argued that the common man tended to blithely believe the clergy’s every word, even suggestions or statements as ludicrous as “the moon is blue” or “the moon is a ball of cheese.”
Over time, the term lost its derogatory top notes and came to be associated with the rare and the uncommon, if not the altogether absurd.
But how did we make the jump between a religious criticism and the second full moon in a calendar month?
One explanation, provided by The Farmer’s Almanac, connects blue with the Old English belewe, meaning “to betray.”
As the Almanac argues, “Perhaps..the moon was ‘belewe’ because it betrayed the usual perception of one full Moon per month.”
Unlike other monthly or seasonal moon names — Buck, Strawberry, Harvest, etc. — the Blue Moon is not restricted to a certain time of year or astrological season.
Astrology 101: Your guide to the star
Astrologer Reda Wigle researches and irreverently reports back on planetary configurations and their effect on each zodiac sign. Her horoscopes integrate history, poetry, pop culture and personal experience.