just got back from bhutan and india, monsoon season, and the M8 was fine. In delhi, it was 100% humidity and the camera was cold from the plane, but warmed up quickly and worked fine.
In bhutan, on and off rain, kept the camera under my shirt between frames, not a problem.
I think if you take reasonable precautions you will be fine. The lack of weather sealing might in fact be a boon, plus the metal body, it warms up fast going from indoors to outdoors. Also I have a regular domke bag for it, so it is not 'sealed' and while it holds some of the cool of the hotel for example, the humid outdoor air mixes in quickly and the camera warms up. In the past with sealed cases like pelicans I have had more trouble with fogging.
anyway, the less AC the better in my opinion for your health! enjoy the trip.