Not that I know of! If you have space on their lawn, the show goes on no matter what the weather. You can vacate your space and go stand along the sides or take shelter under a vendor awning though.

I haven't had a favorable experience in this venue in awhile and I probably wrote some of the nasty comments you've read. The last concert was the final straw for this place for me. Since you have already bought tickets, the only thing I could say more about it is that it's not that massive (compared to a stadium) but your viewing ability is not guaranteed. One of my pet peeves (when it was Pier Six) was that if literally everyone stands in front of you, they won't do anything. If you feel assertive, you can certainly ask to be moved to better seats (if there are any) but it's like pulling teeth to deal with their box office. Not knowing how you procured your tickets, I can only tell you that it's worth a shot. I personally won't give this venue any more of my hard earned money, put up with what it takes to get to Baltimore (not fun), to find reasonable parking (also not fun), and to get into the venue and find your seats. Best of luck and I hope that you have a great experience!