§   An optical phenomenon caused by refraction of sunlight by ice crystals

§   The sky is typically covered by cirrostratus or thick cirrus when it occurs

§   The most common halo is a luminous ring of 22 degrees radius surrounding the sun, with the space within the ring appearing less bright than that just outside

§   On average, solar halo is observed in Hong Kong on about 3 days in a year

Go to top