Overview
- The blue moon will reach peak fullness at about 4:45 a.m. ET on Sunday, May 31, and will look fully illuminated for a day on either side of that time.
- NASA data place the Moon near apogee for this full phase at roughly 252,334–252,360 miles from Earth, which classifies it as a micromoon and makes its apparent diameter about 6–7% smaller than average.
- A calendrical blue moon means this is the second full moon in May; that definition and an alternate seasonal definition are widely used and such calendar blue moons occur roughly every two to three years.
- Visibility depends on time zone and local weather: observers in the Americas, Europe and Africa will see the Moon fullest on the night of May 30 while Asia, Australia and New Zealand will see it on May 31, and the UK Met Office warned of patchy cloud that could affect some views.
- The Moon will not actually look blue under normal conditions; true blue coloration requires rare atmospheric dust or smoke, and viewers wanting crisp photos are advised to watch moonrise near the horizon, use binoculars or a tripod, and consult live streams and NASA’s photography guidance.