Wedding and newborn

Allie
Hi all! I'm trying to plan a wedding and my sister is pregnant and due Aug 3.. I wanted to do it over Labor Day weekend in September but my mom was saying that it would be too hard for my sister to travel then. I don't want to have my wedding when it's cold out seeing as how I already have a tea length gown and the ceremony will be outside in the park ..
So.. When would be a good time for my sister to travel or have a baby at a wedding? She would be traveling from Louisville, KY to charleston, SC (about 9 hours in the car)
Or would it be better to get married in July? I don't want to post pone the wedding all the way till spring 2017!