Hello mspowell. You sound like you have trapped condensation from the air conditioning system in the evaporator housing. See if the passenger floor board is wet. If it is, you need to open the drain for that housing. The drain is located on the firewall at the passenger side. It is located towards the bottom if the firewall and will either look like a round black tube sticking out or have a rubber boot that is slipped over it. You need to unclog it. If it has a rubber boot, pull the boot off and see if it drains. If you have the pipe without the boot, use something like a straw to probe into the hole. You don't want to use something that can damage the items inside the housing. Pursue this track and I think you are going to find your problem.
Your JA Expert,
My passenger side floor board is not wet and there are no signs of moisture in the cabin.