Rare Sun Halo Dazzles Singapore Skies for Four Hours on 15 March

By
Loh Huey Xin
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A spectacular optical phenomenon known as a sun halo captivated Singaporeans across the island on 15 Mar 2025, prompting many to share photos of the unusual sight on social media platforms.

The celestial display was visible for several hours, drawing attention from residents throughout the country.

Widespread Sightings of Celestial Ring Across Singapore Neighborhoods

The bright ring of light around the sun first appeared at approximately 11:00 AM and remained visible until around 3:00 PM, giving Singaporeans ample opportunity to witness the rare occurrence.

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Residents from numerous areas including Chinese Garden, Woodlands, Serangoon Gardens, Bedok, Sembawang, Hougang, Potong Pasir, and Choa Chu Kang reported spotting the rare phenomenon.

Photos quickly circulated across messaging platforms as people documented the event from various vantage points.

Senior Minister Lee Hsien Loong was among those who captured the celestial event, sharing a photo on Facebook at about 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,” SM Lee wrote in his post.

Science Behind the Sun Halo Formation

The striking “rainbow ring” forms when sunlight interacts with ice crystals present in thin, high-altitude clouds.

These clouds are positioned so high in the atmosphere that they consist of ice crystals rather than water droplets, creating the necessary conditions for the halo to appear.

National University of Singapore geography professor Matthias Roth explained that a 22-degree halo specifically 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.

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According to the National Environment Agency (NEA), sun halos are not common in Singapore as they tend to be covered by low to mid-level clouds.

The agency noted that these phenomena typically occur when high-level clouds are blown over the island from immediate surroundings under favorable wind conditions.

The NEA also stated that while it is safe to look at the halo itself with the naked eye, looking directly at the sun without proper protection is dangerous.

Observers are advised to take precautions when viewing such phenomena.

Sun halos are difficult to forecast as the precise location of ice crystals in the atmosphere determines where the halo can be sighted.

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The last comparable sun halo was previously spotted in Singapore on 22 Sep 2020.

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Loh Huey Xin