It doesn't rate rain much or for long except in Sept and Oct.......... that's the "rainy season" in Cancun.
We went late August-early September last year...it rained one night and the party moved to Nice Shoes. We're going the same time this year...if it does rain I'm sure we'll find plenty of indoor activities
I remember one night it rained and Monique and myself just kept dancing in the rain. Then we jumped in the sports pool with all of our clothes. Lol
The few times we experienced some serious rain during the day, the ET's set up some games in the hallway by Nice Shoes and organized pool and ping pong in the Sports Bar. Our group, 8 of us, also played card games in Nice Shoes. They had opened the bar to keep the party going despite the rain. On our last trip (May) we had a torrential downpour but it was a welcome relief from the heat. A lot of people stayed in the sexy pool / hunkered down under Diegos' thatched roof and kept partying.