Rainbows right before sunset have the most vertical alignment possible from a ground-level view, but still are mildly tilted because of the sun’s not being directly along or below the horizontal plane. [Contrast this with a mid-afternoon rainbow that is so tilted as to barely extend above the horizon.] The reddening of sunlight at this time of day, passing through nearly the longest possible cross-section of atmosphere prior to making a rainbow, skews the hue of the entire scene warmly—including the rainbow itself. Very soon, the opposite side of the sky would light up in bedazzling brilliance!
5 ESE Memphis TX (12 May 9) Looking ESE
34.7144, -100.453