I've spent some time travelling in very humid places across Asia, and often I travel with no other safeguards than ziplock bags for my film (which are not in canisters, since they take up too much room). I'm not saying that you shouldn't follow the above advice, since it's better to be safe than sorry, but I've travelled for weeks at a time (Thailand, Cambodia, Burma, Vietnam, Malaysia, Indonesia, etc.) with minimal protection for my film and they've all turned out fine (except infrared...that does suffer from the heat, but I'm sure the expiry dates have something to do with that too).
That being said, now I travel with dessicant packs, plenty of ziplock bags, several microfiber shammies to wipe things down, and only take the amount of film that I think I'll use for the day to keep heat and humidity (and sometimes x-ray) exposure to a minimum.