I too, have to dry outdoors for the same reason. And yes the high humidity can be a problem. Usually the ground powder is too clumpy. Sometimes I think some varieties are just excess oily and will always have some clumping. I dry at around 105 to 110 degrees F and anywhere from 24 to 48 hours usually with some breaks in between for the dehydrator.
Austin has an average morning humidity for June, July, and August of around 85%. The afternoon average for the same period is 45-55%. I am certainly not an expert at dehydrating and hopefully others will respond to your question. Before I grind into powders or flakes I like them, the peppers to feel crispy not to bendy. The pods are sliced to facilitate a more thourough drying.
I would absolutly recommend you try it, but hopefully your dehydrator will be covered or protected from any elements if you leave it unattended.
Good luck, Mike