May 2026 brings with it a small astronomical gift: two full moons in the same month. The first arrived on May 1st, the second — what is conventionally called Blue Moon — will close the month on the 31st. An event that repeats itself on average every two or three years, rare enough to deserve an evening with eyes upwards.
Why is it called “Blue Moon”?
Nothing to do with color: the lunar disk will remain golden-white as always. The name comes from English once in a blue moona figure of speech for something that rarely happens — the equivalent of our “every pope dies.” From this expression was born the astronomical use of the term to indicate the “extra” full moon that sometimes fits into a calendar month.
There is also an older definition, linked to the seasons: in that case the Blue Moon is the third full moon in a season that has four instead of the usual three. Both versions are recognized, but that of May 31, 2026 falls into the monthly category, which is more widespread and popular.
Why does it happen twice in May?
The answer lies in a small misalignment between the cycles of nature and those of the calendar. The Moon takes approximately 29 and a half days to complete its phases; months instead last 30 or 31 days. When the first full moon falls on the 1st of the month, there is exactly enough time for the cycle to end again before midnight on the 31st. This is precisely what happens in May 2026.
The characteristics of this Blue Moon
From a technical point of view, the exact moment of the full moon will be 10:45 am Italian time on May 31st — in the middle of the morning, therefore invisible. But the Moon will appear full in all respects from the evening of the 30th until June 1st.
However, there is a curious detail: this is not just a Blue Moon, but also the micromoon of the yearwhich is the smallest full moon of 2026. It occurs near the apogee, the farthest point of the lunar orbit from Earth. The result is an apparent disk about 7% smaller than average — a difference almost imperceptible to the naked eye, but noticeable when comparing the photographs to those of a supermoon.
From the sky’s perspective, the Moon will shine in the constellation Scorpius, in the vicinity of Antaresthe reddish star that marks its heart. From Italy you will see a suggestive conjunction; in some areas of South America and Antarctica, the Moon will even cover the star for a few minutes.
Where and when to observe it in Italy
The ideal evenings are that of May 30th and of May 31st. The Moon rises in the east around sunset: in the following minutes, when it is still low on the horizon, it takes on a warm, golden hue perfect for photographs with the landscape in the foreground. Later in the evening it will move south, where you will be able to appreciate its proximity to Antares.
For quality observation, it is better to choose an open place towards the east and south-east – a beach, a hill, the shore of a lake – and move away from light pollution as much as possible.
Some advice for photographing it
With your smartphone: stability first of all (place it on a fixed surface or use a mini tripod), manual or night mode, and touch the Moon on the screen, reducing the exposure a little so as not to burn it. Always including a landscape element makes the photo much more interesting.
With a reflex or mirrorless: ISO between 200 and 400, shutter speed between 1/250 and 1/500 of a second, aperture around f/5.6–f/8 and manual focus at infinity. The best time to shoot is right after sunrise, during the golden hour.
Next dates to mark
After May 31, 2026, those who want not to miss the next similar events can note down the May 20, 2027 (Seasonal Blue Moon) and the December 31, 2028 (again monthly). And for those who are curious about the opposite phenomenon: when February does not host any full moon it is called Black Mooneven rarer — the next one will be in 2037.
