Where's Timbo when you need him. I'm sure he can tell us about trying to get a plane off the deck on a hot humid day.
I don't know the details of it, but I know it doesn't work as well as on a nice crisp winters day. Heard too many stories from my pilot friends about trying to get fully loaded cesna's, etc off the runway on hot days.
Is it because on the cold day, the motor has more power, or because the wings have more lift?
Get a flight out of Jidda, Saudi Arabia. You have to leave late at night because the air is too hot and thin during the day for the plane to take off reliably. Been there - got the t-shirt.