Steve CarterWell I never... a rainbow appeared before sunrise, created just by the light of an orange and red glow in the east. There's a first time for everything. I've certainly never see such a thing before.
Marjolein Tamis@GetCarter This is entirely possible! You don't have to be able to see the sun, but the sunlight (hidden just below the horizon for you but visible at higher altitudes) refracts through the raindrops at a higher altitude so you still see the rainbow. It's mostly red and yellow because those colours have the longest wavelengths. Shorter wavelengths scatter over long distances, making green/blue/violet less visible. See also https://www.atoptics.org.uk/rainbows/redbow.htm :)