I had an LSD2 with a bad capsule... it would crackle and drop out with a much higher amplitude than the music I was recording. I sent it to be repaired, they couldn't repeat it. They are in the California desert, and I'm in a reasonably muggy environment. Eventually they did see it when they "gave it the mist test" or something like that, and replaced both capsules with new ones and it was great after that.
The way the tech explained it to me is this.... the capsule has plates a tiny distance apart and they have a voltage across them. Imagine there is a little piece of dust in there... it's supposed to be perfectly clean, but imagine it's not... if the piece of dust is bone dry it doesn't conduct any electricity, but if the piece of dust gets damp, it starts to arc out in there. Hence the way you will frequently see a giant sudden POP and then the signal decays back into normal shape as the charge builds until the next pop. Makes sense to me.
I live in Maine where it gets cold in the winter... I think the big challenge isn't so much the rainy day festivals (which everyone thinks about), it's leaving the mics in the cold car, then pulling them out in the warm club where the condensation builds on them like a cold can of beer on a summer day.