See a second full night of the Full Flower Moon tonight
Due to the exact timing of this Full Moon, we are (technically) seeing it on two nights in a row!
Look up after sunset tonight, to see May's Full Flower Moon lighting up the sky for the second night in a row!
During most months of the year, we advise to look up on one specific night to see the Full Moon. However, for May of 2025, the timing is somewhat unusual, at least for those of us on this side of the planet.
According to the Royal Astronomical Society of Canada's Observer's Handbook 2025, the Full Moon occurs on Monday, May 12 at 12:56 p.m. EDT. That's during the day for those of us in Canada, so we won't actually see the Moon in the sky. The Earth, itself, will block our view at that time.
Fear not, though! We're not going to miss it!
Given the Moon's distance and its apparent size in our sky, it's challenging to notice very small changes in its illumination. So, we have a bit of leeway here.
With over 99 per cent of the Earth-facing side illuminated by the Sun from moonrise on Sunday, May 11, through moonset on the morning of Tuesday, May 13, we can enjoy two full nights of the Full Moon!
DON'T MISS: Look up! What's going on in the May night sky?
What is a Flower Moon?
The May Full Moon often goes by the popular name Flower Moon.
This is one of the names gathered and written down by the Farmer's Almanac in the early 20th century, giving one name to each of the 12 typical Full Moons of the year.
This graphic collects all the relevant data about each Full Moon of 2025, including their popular names, whether they are a 'super' or 'micro' Moon, a perigee or apogee Full Moon, and whether they are remarkable in some other way, such as a Harvest Moon or a lunar eclipse. (NASA's Scientific Visualization Studio/Fred Espenak/Scott Sutherland)
The names they chose were mostly inspired by the lunar calendars of indigenous peoples living in Canada and the United States, especially those from around the Great Lakes and what is now the US Northeast. A few, such as Wolf Moon and Hunter's Moon, were also drawn from Colonial and European folklore, as well.
"Flower Moon" originates from the Anishinaabe, a group that includes the Algonquin, Odawa, Ojibwe, Mississaugas, Nipissing, and Potawatomi peoples. However, this name was likely simplified from the original, which was closer to Blooming Moon, Budding Moon, or Planting Moon. It was also referred to as the Sucker Moon or Suckerfish Moon.
It's important to note that indigenous lunar calendar names did not apply only to the Full Moon.
Like many advanced cultures around the world, the indigenous peoples of North America tracked their year using a lunar calendar that treated each 'moon' the same way that the Gregorian calendar uses a 'month'.
So, each moon name actually refers to a full 'lunation' — the roughly 29-day period between that particular Full Moon and the next. Thus, 2025's "Flower Moon" is the period of time between the night of May 12 and the night of June 9.
READ MORE: Even the Micromoon looks huge? What is the mysterious Moon Illusion?
And a micromoon?
At a casual glance, each Full Moon can appear the same as any other. However, if you look closely, they are actually all fairly unique.
The orbit of the Moon for May 2025, with each corresponding lunar phase shown. Although the orbit may appear circular at this scale, it is, in fact, an ellipse, as the distances of the Full Moon (406,006 km) and New Moon (375,871 km) demonstrate. (NASA's Scientific Visualization Studio/Fred Espenak/Scott Sutherland)
As the Moon orbits around the Earth, it follows an elliptical path. It's average distance is considered to be 384,400 kilometres (or one "lunar distance"), but for about half of each orbit the Moon is closer to Earth, and it spends the rest of the orbit farther away.
That change in distance affects the Moon's apparent size in our sky, causing it to grow and then shrink, in a fairly regular pattern.
Early on Sunday, the Moon will be near its farthest distance to Earth for the month. With the Full Moon occurring only a day and a half after it passes through apogee, this Full Moon will be a micromoon. It will appear about 90 per cent as bright as a typical Full Moon, and it will be only a little over three-quarters as bright as the Perigee Supermoon we'll see in November.
The phases of the Moon for May 2025, showing how the Moon appears smaller and smaller in our sky through the first half of the month, as the Moon reaches apogee (its farthest distance from Earth), and then larger and larger throughout the rest of the month, as it passes through perigee (its closest distance to Earth). (NASA's Scientific Visualization Studio/Scott Sutherland)
"Micromoon" isn't, technically, a real scientific term, by the way. It's simply the opposite of a "supermoon" — a term invented by astrologer Richard Nolle in 1979. Nolle defined a supermoon as "a new or full moon which occurs with the Moon at or near (within 90 per cent of) its closest approach to Earth in a given orbit (perigee)."
As such, a micromoon is "a new or full moon which occurs with the Moon at or near (within 90 per cent of) its farthest approach to Earth in a given orbit (apogee)."
This apparent change in the Moon's size doesn't look the same each month, though. The influence of the Sun and other planets causes the Moon's ellipse to change shape slightly on each orbit around Earth. So, nearly every Full Moon occurs at a different distance to Earth, and is thus a slightly different size in our sky.
The Full Moons of February through June of 2025, arranged to show how the Moon appears smaller each month from February to March to April, and then appears larger from April to May to June. (NASA's Scientific Visualization Studio/Scott Sutherland)
This results in a second pattern that plays out throughout the year. We see one Full Moon that's the farthest, smallest and dimmest Full Moon of the year, known as the Apogee Moon. This was April's Pink Moon. At the other 'end' of the year, there will be a closest, biggest, and brightest Full Moon of the year, known as the Perigee Moon. This will occur in November.
(Thumbnail image courtesy "Dave K", from Owen Sound, who took this picture of the Full Flower Moon on May 6, 2023.)