Well honestly I got too much water but I can't imagine humidity being an over riding factor. It is all about the media and the water.
For the first three years I grew them in straight sphagnum moss . I thought that they did great. But then I started to rot some, especially Cycnoches species and primary hybrids. So this is why I am trying this layered media. I hoped to dry them out more quickly from June to September, our rainy season. I get 40+/- rainfall for 4 months!! Incredible. The dry months I water often enough so they do not go bone dry.
Example of difference: Catasetum tenebrosa flowers for me two or three times with a dozen to fifteen flowers. This year, twice so far with 21 and 23 flowers on a taller and stronger spike.