Rare sun halo spotted across Singapore skies
A rare sun halo appeared over Singapore on 25 August 2025, forming a luminous ring around the sun visible across several areas. The phenomenon occurs when sunlight refracts through ice crystals in high-altitude cirrus clouds, conditions rarely met in Singapore’s warm, humid climate. Photography enthusiasts documented the event, which follows a similar sighting in March this year.
- A sun halo, caused by sunlight interacting with ice crystals in high-altitude clouds, was visible across Singapore on 25 August 2025.
- Such events are uncommon in Singapore due to the typical low to mid-level cloud cover and warm climate, making sightings notable for observers and photographers.
SINGAPORE – A rare optical event known as a sun halo appeared in the skies over Singapore on 25 August 2025, captivating observers and prompting photography enthusiasts to document the phenomenon across the island.
The halo, appearing as a luminous ring encircling the sun, was visible in multiple locations around midday and early afternoon. This marks the second such sighting this year, following a similar event on 15 March.
How sun halos form
Sun halos occur when sunlight interacts with ice crystals suspended in high-altitude cirrus clouds. The crystals refract sunlight at a specific angle—commonly 22 degrees—producing the halo’s characteristic circular appearance. The 22-degree halo is the most frequently observed type.
Formation of such halos requires ice crystals to maintain consistent shapes and orientations within upper-level clouds, conditions that are rarely met in Singapore. The country’s typical cloud cover consists of low to mid-level clouds, and its warm, humid climate does not favour the development of the high, ice-filled cirrus clouds necessary for halos to form.
Observation patterns and frequency
The National Environment Agency (NEA) has noted that predicting the presence and position of cirrus clouds is challenging, making accurate forecasting of halo appearances difficult.
The March sighting was recorded from areas including Chinese Garden, Serangoon Gardens, Bedok, and Woodlands, with halos visible between 11am and 3pm. The August occurrence followed a similar pattern in both timing and distribution.
Other documented sightings in recent years include 22 September 2020 and another event in 2021, suggesting that sun halos appear in Singapore only once every few years.
Safety and public interest
While the halo itself is safe to observe with the naked eye, experts remind the public that looking directly at the sun can be hazardous and proper eye protection should be used.
The rarity and visual appeal of sun halos make them popular among photography enthusiasts and casual observers alike, offering a striking reminder of the interplay between atmospheric conditions and light.
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