I live in GA, temps can hit 100+ and in the summer, any dark carpet makes one very much hotter to fish out of. If you tried to give me a brand new 21' Ranger with dark carpet and told me I had to leave that carpet in it, and fish in the summer with it, I would refuse the offer.
Up north, I'm sure it's a little different, but in the southern sun, not even dark grey, blue, red, etc is going in my boat, been there done that one time, cost me a bunch of time and money, won't happen again.