Blue Moon 2026: Rare Second Full Moon To Light Up Sky On May 31

Skywatchers will witness a rare astronomical event in May 2026, when a second full Moon will appear at the end of the month. The first full Moon appeared on May 1, while the second will appear on May 31, reported BBC.

Because the second full Moon falls within the same calendar month, it is known as a blue Moon. The event also means that 2026 will have 13 full Moons instead of the usual 12.

Why Blue Moons Happen

A blue Moon happens because the lunar cycle does not perfectly match the calendar year. A day is based on the time Earth takes to rotate once on its axis, while a year is the time Earth takes to orbit the Sun. A month is linked to the Moon's orbit around Earth.

Usually, there is one full Moon every month, which is why many full Moons have traditional names connected to seasonal changes in nature. Examples include February's Snow Moon, June's Strawberry Moon and December's Cold Moon.

However, 12 lunar cycles are around 11 days shorter than a calendar year. Because of this difference, some years include an extra full Moon, resulting in two full Moons appearing within a single month.

The first full Moon of May 2026 appeared on May 1 and is known as the Flower Moon. The name is linked to springtime, when flowers are in bloom.

Since there are around 29.5 days between full Moons, another full Moon will rise before the month ends.

As a result, the full Moon on May 31 will be classified as a monthly blue Moon.

Where The Full Moons Will Appear

The blue Moon on May 31 will rise in the east, but it will appear lower in the sky and just to the right of the constellation Virgo.