Look up! A ‘Blue Moon’ lights up the sky on the evening of May 31

So here's the thing about Blue Moons: they're not actually blue. Bit of a letdown, really, but stick with us. On May 31, Bangkok gets treated to one of these oddly-named lunar events, and while it won't glow sapphire across the sky, it's still worth your attention. The ‘blue’ bit? Pure scheduling. It simply means an extra full moon's snuck its way onto the calendar, making it more of a celestial admin quirk than a proper light show.

And yes, those striking cobalt-blue moons all over social media are usually the work of photography tricks rather than the night sky suddenly turning theatrical. Most blue-tinted moon images are created using camera filters or editing software such as Photoshop, though rare atmospheric conditions can occasionally give the moon a bluish hue. Usually, however, it stays its familiar silvery shade.

The last one landed back on August 19, 2024, when stargazers got a seasonal Blue Moon – meaning it was the third full moon within a season containing four. That particular lunar event also doubled as a supermoon, kicking off a run of four oversized moons across 2024. Big, bright and unusually close to Earth, it put on quite a spectacle.

This year's version heads in the opposite direction. The May 31 Blue Moon is also the most distant full micromoon of 2026, which sounds faintly insulting but is actually fairly fascinating. A micromoon happens when the moon reaches apogee, the furthest point from Earth during its orbit. As a result, it appears noticeably smaller than a supermoon and slightly tinier than your average full moon. Not dramatically so, but enough for dedicated moon-watchers to spot the difference.

You can start looking up from early evening onwards, preferably somewhere with a clear stretch of sky and minimal city glare. Bangkok's rainy season may have other ideas, with thick clouds likely rolling across town by sunset. Still, weather in this city changes its mind every five minutes, so it's worth keeping an eye on the sky anyway. A rare lunar event and an excuse to stand outside for a while? Could be worse ways to spend a Saturday night.