A runner spotted a “fire rainbow” over the Pinnacles National Park in California.
A fire rainbow, known as a circumhorizontal arc, occurs when the sun is more than 58 degrees above the horizon. The sun must be higher than this in order for the arc to form.
Then, as the sunlight is refracted off of the ice crystals in cirrus clouds you get the pretty colors.
according to Atmospheric Optics, a fire rainbow can be spotted five or more times during the summer.