Weather Words: 'Lunar Halo'

A lunar halo is an optical phenomenon caused by the reflection and refraction of light through ice crystals within high-altitude cirrus or cirrostratus clouds. These haloes are also referred to as “22-degree haloes” because the light passing through the ice crystals is bent at a 22-degree angle.

Interestingly, these haloes can be a decent (though not perfect) predictor that rain will come soon. That’s because cirrus clouds often precede rainstorms. In fact, there’s even an old rhyme from weatherlore that goes “ring around the moon, rain soon.” So the next time you see a lunar halo, keep your umbrella handy the next day, just in case.

• A​pricate
• D​ebacle
• J​ellyfish Clouds
• M​ackerel Sky
• Snow Rollers

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