A Rare ‘Blue Moon’ Is Coming — What It Really Means

BreakingInnovationScienceA Rare ‘Blue Moon’ Is Coming — What It Really MeansByJamie Carter,Senior Contributor.Forbes contributors publish independent expert analyses and insights. An award-winning reporter writing about stargazing and the night sky.Follow AuthorMay 27, 2026, 03:00am EDTToplineA full Blue Moon is coming this weekend — and despite the name, it has nothing to do with color. Early on Sunday, May 31, the moon will become full for the second time in a single calendar month, creating what’s commonly known as a monthly Blue Moon. It’s a simple quirk of timing, caused by the mismatch between the moon’s 29.5-day cycle and our calendar months. Here’s everything you need to know about the Blue Moon 2026. A second full moon in a single calendar month will occur on May 31 and be best seen at moonrise on May 30. (AP Photo/Michael Probst)Copyright 2026 The Associated Press. All rights reservedKey FactsA rare Blue Moon is coming — the second full moon in a single calendar month, caused by the mismatch between the moon’s 29.5-day cycle and our calendar.It will occur on Sunday, May 31 — though it will be best seen at moonrise on Saturday, May 30, when it rises in the east during dusk.On Saturday, May 30, it appears on the eastern horizon at sunset, glowing orange — thanks to how Earth’s atmosphere scatters light — not blue.The next monthly Blue Moon, like this one, will take place on Dec. 31, 2028. However, there’s a seasonal Blue Moon on May 20, 2027. if (!window.cnxel) { window.cnxel = {}; window.cnxel.cmd = []; var iframe = document.createElement('iframe'); iframe.style.display = 'none'; iframe.onload = function() { var iframeDoc = iframe.contentWindow.document; var script = iframeDoc.createElement('script'); script.src = '//cd.elements.video/player.js?cid=62cec241-7d09-4462-afc2-f72f8d8ef40a'; script.setAttribute('defer', '1'); script.setAttribute('type', 'text/javascript'); iframeDoc.body.appendChild(script); }; document.head.appendChild(iframe); const preloadRes...