Residents across the North Island of New Zealand observed an unusual atmospheric display today: a 22⁰ circular halo around the sun.
A Common, Yet Striking, Phenomenon
The MetService shared an image of the halo on social media, explaining it was created by light refracting through hexagonal prism-shaped ice crystals in a thin veil of high cloud cover. According to the forecaster, this phenomenon is surprisingly common, occurring even more frequently than rainbows.
The MetService detailed the process: “Light is refracted as it enters through one face of the hexagonal ice crystal, and is refracted once more as it exits through another face.” The geometry of the crystals causes light to deflect at angles between 22⁰ and 50⁰, with a concentration at approximately 22⁰, resulting in a brighter circle around the sun.
Social Media Captures the Sight
The striking visual prompted many to share their own photos online. Tracey Lee, a resident of Tauranga, shared a picture with 1News, noting she had previously witnessed the phenomenon a few years ago.
If conditions remain favorable – specifically, the presence of thin, high clouds – similar halos could be visible again in the coming days. The appearance of these halos is dependent on specific atmospheric conditions and is not predictable with long-term accuracy. It is possible that further displays will be observed as long as the necessary ice crystals are present in the upper atmosphere.
Frequently Asked Questions
What causes a sun halo?
A sun halo is created by the refraction of light through hexagonal ice crystals suspended in high-altitude cirrus or cirrostratus clouds.
Are sun halos rare?
According to the MetService, sun halos are actually quite common and occur more frequently than rainbows.
Is a sun halo a sign of changing weather?
The source does not indicate that a sun halo is a sign of changing weather, but rather a result of specific atmospheric conditions.
Have you ever witnessed a sun halo or similar atmospheric phenomenon, and what was your initial reaction to seeing it?
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