What aboutNot really, at least in my opinion. The state of "working in vain" won't occur until it rains (if it does), so we won't know until tomorrow if we have worked in vain.
"If I choke on the exam tomorrow, all my studying will have been in vain."
We're talking about a future event that could change our evaluation of something in the past, and we're talking about it at the point between the two. I think it's a pretty powerful language structure.