The simple all around fix is to simply use some powder. Simply throw some on the screen and spread it around with your hand to spread and coat evenly the film side of the screen right before exposure.
Controlling the humidity takes more attention, time and energy and you are chasing a seasonal / weather influenced / geographic variable.
We have experimented with over drying screens in a 95- 100 degree environment for 6 hours and the ink still stuck to the emulsion.
We have tried damprid
http://www.damprid.com/ in a closed cabinet with coated screens and some ink still sticks.
Remember (at least in our situation) it is not the film that sticks to failure but the ink coating on the film.
Yes our waterproof films did stick to the emulsion in the worst cases but the true damage came when the ink pulled off the film creating a DTS the hard way!!!!
Like everyone the issue here in the north east was way worse in the spring / summer than in winter.
the stop drop and roll fix, (in our multi hundred $ business) is simply to stop trying to fix the environment and throw some powder on the darn screen. .......................Just go print something and leave the environmental issues to Al Gore
mooseman