Usually weather in the Riviera Maya is fantastic. It can also be just as good, but a bit cooler, in the wet season.
With weather its always a big guess. All I can really tell you is that the chances of having rain are greater. The way I like to look at it. It might rain, but it will be a warm rain!
If weather does bring a damper on your day... the biggest difference you can make is keep a positive attitude and smile on your face. Your guests will love it if you do!
Best of luck
Lincoln & Lori