Rain isn't an issue, plan your camp as usual on high ground, snow just camp right on top of it like a normal tent (a tent floor is not good insulation). This will be my first year but plenty of guys that use these have been in downpours with no water issues, i'll put a piece of tyvek under my pad. Also if cold enough pack a stove and it will dry stuff out quick.
Oh yeah, if you take the stove add 1.5 - 2.5lbs to shelter weight depending on brand.