A sun halo was visible across Singapore on March 15, 2025. Many residents took photos of the phenomenon and shared them on social media.
The bright ring of light around the sun was visible from 11:00 AM until about 3:00 PM.
Residents in Chinese Garden, Woodlands, Serangoon Gardens, Bedok, Sembawang, Hougang, Potong Pasir, and Choa Chu Kang reported seeing the phenomenon.
Senior Minister Lee Hsien Loong shared a photo on Facebook at approximately 2:40 PM. “A rare and spectacular sight in the skies above! I am told that this phenomenon is known as a 22-degree halo or a sun halo,” he wrote.
The rainbow-like ring forms when sunlight passes through ice crystals in high-altitude clouds.
National University of Singapore geography professor Matthias Roth explained that a 22-degree halo refers to the ring of light having a radius of about 22 degrees from the sun at its center.
“As light enters one face of the ice crystals and exits through another, it is bent by about 22 degrees, which accounts for the radius of the halo,” Professor Roth said.
The National Environment Agency (NEA) stated that sun halos are not common in Singapore because they are typically covered by low to mid-level clouds.
The NEA warned that while looking at the halo is safe, looking directly at the sun without protection is dangerous.
Sun halos cannot be easily predicted as they depend on the exact location of ice crystals in the atmosphere.
The last similar sun halo was seen in Singapore on September 22, 2020.
