You will find that happens with the outlets outside and other damp locations also. Every time it rains or snows, my Christmas lights go out because I followed the rules and put a GFCI on the front porch.
How they work, they monitor the amount of current going and coming on both the black and the white. According to one of those old dudes, there is a law that the current in a circuit is equal in all parts of the circuit. If you accidentally get onto the circuit with your body, that will be another pathway for the current to go through, and that makes an imbalance on the black and the white wire in the GFCI. It recognizes this imbalance and trips. There is a threshold for the amount of imbalance, don't know what it is off the top of my head.
But any dampness around the outlets can cause stray currents, which will imbalance the circuit in the GFCI and cause it to nuisance trip. Just the nature of the beast.