In there summer, there are times when you'll see a hazy ring around the sun or moon. This is a pretty reliable sign that the weather is going to change soon, typically it means rain is on the way. The halo that can form around a bright object, like the sun and moon, is caused by the refraction of light through ice crystals in high altitude cirrus clouds, which are often the first cloud to appear ahead of a front. The halo can also be caused by diffraction of light around water droplets in clouds as it travels from the light source to our eyes, causing the appearance of a halo. So, when you see a halo around the sun or moon, know that the atmosphere is changing and the weather is likely to change in the next 18 to 36 hours!