A Rare Blue Moon Will Light Up Spanish Skies on May 31 — Here's What to Know

Two Full Moons in One Month — A Rare May Treat

Skywatchers across Spain are in for a treat this May: the month will contain two full moons, with the second — falling on Sunday, May 31, 2026 — earning the title of a Blue Moon.

The first full moon of the month arrives on Thursday, May 1, traditionally named the Flower Moon. The second, on May 31, is the Blue Moon. Because of this extra full moon, 2026 will have 13 full moons in total instead of the usual 12 — an occurrence that only happens every two or three years.

What Is a Blue Moon?

Despite the evocative name, the moon will not actually turn blue. A Blue Moon simply refers to the second full moon within a single calendar month — or, in an alternative definition, the third full moon in a season that contains four. The name has nothing to do with colour, and everything to do with rarity.

The phrase "once in a blue moon" — meaning something that happens very rarely — comes directly from this phenomenon. Seeing two full moons in one calendar month is genuinely uncommon, which is why it has captured imaginations for centuries.

All 13 Full Moons in 2026

The full moon calendar for 2026 makes for interesting reading — it also includes a total lunar eclipse in March and a partial lunar eclipse in August:

• 3 January — Wolf Moon
• 1 February — Snow Moon
• 3 March — Worm Moon (total lunar eclipse)
• 2 April — Full Moon
• 1 May — Flower Moon
• 31 May — Blue Moon
• 30 June — Strawberry Moon
• 29 July — Buck Moon
• 28 August — Sturgeon Moon (partial lunar eclipse)
• 26 September — Harvest Moon
• 26 October — Hunter's Moon
• 24 November — Beaver Moon
• 24 December — Cold Moon

How to Get the Best View

Spain's climate makes it one of the better places in Europe for moongazing, particularly in the south and on the islands. For the clearest view of the Blue Moon on May 31:

• Head somewhere with as little light pollution as possible — rural areas and open natural spaces are ideal
• Check the exact moonrise time for your location — the moon is often most dramatic just as it clears the horizon
• Clear skies are forecast across much of southern Spain in late May, though conditions can vary

Whether you are a dedicated astronomer or simply someone who enjoys an excuse to look up, the Blue Moon on May 31 is worth marking in the calendar.

This article is based on reporting from Spanish News Today, published April 30, 2026.