is there a 2nd rainbow in the top rhs just below the tree? also the color changes below the rainbow would be because of the different speeds of light possibly? or the location of the sun could have caused it

Imo light speed is allways same, so reason why color changes to lighter blue under the rainbow has nothing to do with it. If you look at rainbow pics, youll notice same thing on all of them, atleast on rainbows like this one

if light speeds were always the same you wouldn't see the rainbow

different colors have different wave lenght so they bounce at different angle from water drops and thats why you see the color spectrum like that.

ok i'm just overtired and brain wasn't working. but there is probably a logical reason why its lighter below the rainbow ; my brain is just too tired

i tried looking from wikipedia to find reason for that, but didnt find eny reason, but its not just this pic that it happened, it happens everytime on big rainbows like that imo.