Good question. I'm seeing more and more outdoor projection screens. My 4x8 sheet of Formica isn't afraid of the rain, why should the speakers be afraid of the rain ?

Then again, between winter snow, spring rain and summer black flies our outdoor HT season is only about three weeks most years

However, a picnic shelter with a regular Epic 80-600 system would probably be just fine. A big fire in winter and spring (and fall), and screens around the periphery in the summer...

Hmmmm.

M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8