I suggest getting a pro body that has the seals needed to help keep the moisture out. I am constantly going in and out of places with huge temperature differences, including swimming pools. Nothing like going from 10 degrees above 0 to 80 and nearly 100% humidity at a high school swim meet!
Humidity is tough on cameras. I have even shot football games where you would swear it was raining looking at the camera, water dripping off it, but it works fine (well before the auto focus croaked recently - not due to humidity though). I had one camera that wouldn't even turn on if it was too humid.

JS