There isn’t any evidence that creatine helps endurance efforts in hot conditions. But there is no evidence that it hurts, either! One thing creatine definitely does for me is suck ~5lbs of fluid into my muscles so in a climby race like BCBR that’s one thing to consider.
If you want a protocol that definitely helps endurance performance on a hot day, consider the greenleaf/sims hyper-hydration protocol (previously discussed on this forum). That is something that has helped me a lot in the past.