Why do the words "gently down the stream" pop into my head?

I'd definitely try things out on a nice night - you want to figure out your pitch (especially if you're doing something more complex than an A-frame.)

Is the rain different in your piece of the Big Dirty? The rains I experienced were all-day or all-night (or both), soaking rains that went from light to "...build it 40 cubits by..." and lasted a couple of days. If your worst storms are only a few hours, rain might not be as big a deal as it is around here.

Another thought: are your long, soaking rains confined to one season? If so, you might want to just avoid those seasons. At 72, my "I can camp in the rain" t-shirt is still intact, and since I don't collect them, I now just opt to stay home when significant rain is in the forecast.