Almost the Same Weather?

I ran a marathon 2 and a half weeks go, and I'm scheduled to run another in a few days, and I really hoped that this Sunday would be notably cooler than that Sunday 2 and a half weeks ago, but it's shaping up to be just a teeny bit cooler. Well, every little bit helps

The course will also be a slightly flatter.
But what if I've gotten slightly fatter?