Yep. I've had it happen once or twice. What I did notice is that if it rained before and it's still slippery, they sometimes (or maybe always?) start the music and the fireworks and then announce a special meet and greet with Mickey, Goofy, Donald and Minnie in their Dreams outfits.
Another weird instance was on 1/29, I was watching the first showing of DAWM and it was bare bones. No fireworks in the beginning, no moving mouths, one dance couple missing and the tower didn't go up. But then later that night, everything was back to normal. It was a Pirate and Princess Party day and I know they do DAWM later in the night for the party so maybe the early three showings in afternoon had to be bare bones? It was strange
It was funny watching Celebrate the Season on 12/21 (I had already seen and taped the first showing of the night) it had lightly started raining but they still started the show but once the dancers came out it suddenly stopped. Just funny to see it stop so seamlessly.