Unfortunately, those within the weather world would be quick to tell you that what you might call a fire rainbow is actually a circumhorizontal arc. All extremely long adjectives aside, the smoking-hot rainbow you might be fortunate enough to witness swaying among the clouds is actually cold as ice and not related to rainbows at all.
Known as the rarest of all naturally-occurring phenomena, for the fire rainbow to be seen very specific elements must be at play: first of all, the clouds through which the light refracts must be at least 20,000 feet in the air and must also be of the cirrus variety. Further, the sun has to be elevated at an angle of precisely 58 degrees.
What this often translates to is that those picnicking in the park in the United States are more apt to be warmed by the icy light’s technicolor rays than those in Northern Europe given the region’s extreme fluctuations in sunlight. Sorry, Denmark.