You know what, I get it, even though I laughed at first.
The question "what is humid" means -- "what is the proper humidity for a chameleon?"
The answer depends upon your species but here's my theory -- Chameleons need to drink lots of water more than breathe humid air. Constant humidity is not as important for most chameleons as a daily offering of drinkable water.
SO it's more important to have one 20 minute misting interval followed by dry all day and less important to have 20 quick sprays to keep humidity up. Keeping things wet all day is not clean.