How often do you use it ?
I'm in central Florida and do pretty much NOTHING except keep the batteries up. How you do that depends on where it's parked and how good your built-in charger is.
I worry more about varmints and bugs than humidity.
I try not to solve problems until I know for sure that they actually exist.
I do not drink the water from the tank so I don't worry too much about that.
As long as you don't have an internal source of humidity......like a water leak, the heat buildup should keep the moisture content lower than it is outside. As long as there is no condensation, a relatively high humidity should not be a problem.
Others will, no doubt, have widely varying opinions.