That is actually ideal. Your vines were the most recently protected from the wet conditions from the rain. Worst is it rains then you spray, since damage from fungus can occur in hours after a rain, which is often before you can spray.
And if you have dry weather after the rain, you are most likely just fine.
But it you spray and you have rain and high winds for two weeks, like I had last year, then you may have problems. But that is farming. If farming was easy, everyone would do it.