Gfci Continues to trip in wet weather.

The previous day, I went around making sure all my plugs are taped, and off the ground at least a half inch. What a nightmare. So when my gfi blew, I decided to test each channel, nothing blew, channels 1-16 on, no problems, then I can turn on all the channels fine, by fading them on, if I try to go form off to on, then it trips. So I figured my gfc was being oversensitive, so I unplugged the gfc and plugged it in right to the wall (I have a removable gfc) I was stumped as to why it would not trip with only one channel on at a time.The next dry day I put my gfi back and no problems, so its the rain for sure causing the problem. My show only takes 10 amps max, 2200 mini lights and 25 c9's - so I cant possibly be overloading it.