A Blue Moon Is Visible Across Spain on 31 May — Here's What It Actually Means

On 31 May, Spain will be able to observe a Blue Moon — a rare astronomical event that occurs once every two or three years.

Despite the name, the Moon will not change colour: the term refers to the phenomenon of two full moons occurring within a single calendar month. The first full moon of May fell on the 1st. The next Blue Moon is not expected until late 2028.

The best time to observe it is the night of 30–31 May and the night of 31 May itself. The Moon will rise above the horizon shortly after sunset with a reddish or orange tint, before taking on its usual colour.

This year's event has an additional feature: it coincides with a micromoon — the moment when the Moon is at its furthest point from Earth in its orbit and may appear slightly smaller than usual. Experts note, however, that the difference will be difficult to detect with the naked eye.

The Blue Moon will be visible from anywhere in the country under clear skies. Astronomers recommend choosing locations with minimal light pollution, an open horizon, and a clear view to the east: beaches, viewpoints, rural areas, or mountain settings.