Millions of tiny ice crystals caused the fabulous show above St. Louis’ skies, according to NASA.

MISSOURI, USA — Ahead of the brightest and closest moon sighting of 2025 on Wednesday morning, the moon gave St. Louis residents a different kind of show Tuesday night.

Multiple people throughout the St. Louis region posted pictures to the 5 On Your Side Weather Watchers page showing a bright ring around the moon ahead of Wednesday morning’s supermoon. 

“222,383 miles away, and still an amazing sight to see,” Weather Watcher Jim Trettenero from Staunton, Illinois, said.

“Check out this moon halo right now from Lake St. Louis! If you can go look at it yourself!” said Weather Watcher Sophia Scott from St. Charles County.

The visual effect is known as a lunar halo or a 22-degree halo, and it’s caused by light from the moon hitting millions of tiny ice crystals when high-altitude, wispy clouds cover much of the sky, according to NASA. The light then refracts, or changes direction, and causes the bright, white ring.

“Each ice crystal acts like a miniature lens,” NASA said on its website. “Because most of the crystals have a similar elongated hexagonal shape, light entering one crystal face and exiting through the opposing face refracts 22 degrees, which corresponds to the radius of the Moon Halo.”

There’s still some mystery regarding the phenomenon. Researchers are still trying to understand exactly how ice crystals form in clouds. The Manchester Ice Cloud Chamber, a 32.8-foot-tall cylinder used to simulate conditions found in the upper atmosphere, is working to understand the process and how it relates to ongoing studies regarding climate change.