Rare Blue Micromoon Lights Up May Skies

Stargazers are in for a special treat on May 31 as a rare blue micromoon adorns the night sky—a phenomenon that won't occur again until December 2028. This event, noted by WGAL and covered by CBS News, is drawing attention from amateur astronomers and casual skywatchers alike for its rarity and unique characteristics.

What Is a Blue Micromoon?

A blue moon is commonly defined as the second full moon in a single calendar month, though some traditions use a seasonal definition. In this case, the May 31 event is the second full moon of May, making it a calendar blue moon. The term "micromoon" refers to a full moon that occurs when the Moon is near its apogee, or the farthest point from Earth in its orbit, making it appear smaller and dimmer than usual.

While the moon won't literally turn blue, the title highlights the infrequency of the event. According to NASA's eclipse catalog, blue moons occur about once every two to three years, but the combination with a micromoon is especially unusual.

How Rare Is This Event?

• The next blue micromoon will not occur until December 2028, making this a once-in-a-multi-year skywatching opportunity.
• According to the U.S. Naval Observatory's records, blue moons and micromoons only coincide occasionally, adding to the rarity of this event.
• Sky & Telescope's analysis of blue moon timing confirms that the May 31 event is the only such combination for several years.

Viewing Tips and What to Expect

The blue micromoon will be visible worldwide, weather permitting. Because the moon is at apogee, viewers may notice it appears slightly smaller and less bright than a typical full moon—often about 14% smaller and 30% dimmer than a supermoon. For best viewing, find a location with a clear horizon and minimal light pollution.

While no special equipment is needed, binoculars or a small telescope can enhance details on the moon's surface. The International Meteor Organization's meteor shower calendar shows that no major meteor showers coincide with this event, allowing the moon to take center stage.

Looking Ahead: Next Blue Moons

If you miss this blue micromoon, the next chance to see a blue moon won't come until August 2027, but it will not be a micromoon. The next blue micromoon is expected in December 2028. For a full list of upcoming blue moons and their types, reference the comprehensive tables at NASA's eclipse catalog and the blue moon explainer from timeanddate.com.

Conclusion

Whether you're a seasoned astronomer or a curious observer, the blue micromoon of May 31 is a reminder of the subtle wonders our night sky offers. With its rarity and delicate beauty, this event invites everyone to step outside and look up, appreciating a celestial rhythm that won't repeat for years to come.