08/12/2025
Only Jeremy Lewan could track a rainbow right to AAA North Penn. 📍🌈 That’s next-level forecasting!
I had just finished shopping at Style Encore in Dickson City when I saw this phenomenon for the first time in my life—a circumhorizontal arc!!! 🌈
Although it’s not exactly rare here in the U.S., I have never seen one before, and I was so excited to witness it after only ever seeing it in my meteorology textbooks. 📚
It is sometimes misleadingly called a “fire rainbow,” but it is NOT a rainbow. Rainbows are formed by reflection and refraction within RAINDROPS. 💧
This is a type of ICE halo, formed by the refraction of sunlight when the sun is high in the sky (more than 58° in elevation). The refraction occurs in plate-shaped ice crystals within clouds suspended high up in the atmosphere where it’s cold enough to support ice, typically in cirrus or cirrostratus clouds. (In this case, it’s cirrus clouds—the whispy ones in the back!) ☁️
In its full form, the circumhorizontal arc manifests as a large, brightly spectrum-colored band (red being the topmost color) running parallel to the horizon. The distance between the arc and the Sun is twice as far as the common 22-degree halo. 🌞
This one was quite long—oftentimes they’re much shorter than this! When the halo-forming cloud is small or patchy, only fragments of the arc can be seen. As with all halos, it can be caused by the Sun as well as (but much more rarely) a full or bright Moon. 🌕
