A blue moon is a rare second full moon in the same calendar month. We’re lucky enough to have one at the very beginning of this May and one at the very end.
Once in a Blue Moon 🔵
— NASA's Glenn Research Center (@NASAglenn) May 29, 2026
While the Blue Moon that you'll be able to spot in the night sky this Sunday, May 31, won’t actually appear the color blue, it will still be a rare sight!
This name refers to a second full Moon visible in a single calendar month. pic.twitter.com/ymeS9i54Sy
Skies were mostly clear last night, as the moon rose at 8:19 p.m. very close to 99.6 percent full. Tonight, a few high and mid-level clouds are possible as the full Blue Moon rises at 9:17 p.m. Still, solid viewing.
Final cool facts: It’s size appearance in the sky will be smaller-than-usual full moon by ~10 percent. Also, a blue moon only comes around about every two to three years. More reason to enjoy it this weekend!
