What are solar halos?

Solar halos are a somewhat common sight, but do you know what they are?

Seen above, this example was sent in by Tony Tye in St. Helens. Halos are a visual phenomenon caused by suspended ice crystals in the air.

The sometimes colourful, often white light circles, arcs and spots in the sky appear via refraction and reflection of sunlight through ice crystals in cirrus clouds in the sky.

As the phenomenon involves light, it is not just tied to the sun but to the moon as well. On bright nights with a full moon, we can see lunar halos appear overhead. You may have heard the myth that a ring around the moon means rain soon.

When a storm approaches, it does not arrive all at once. Both cirrus and cirrostratus clouds act as forerunners in the upper levels of the troposphere.

At night, the moon shines through these clouds and their ice crystals. The more moisture in the atmosphere, the more likely a halo will appear. The more moisture, the greater chance of rainfall.

If you see this phenomenon near you, be sure to take a picture and send it to use via the uploader or tapping the image icon in the app.