My DH and I went to
MVMCP 3 years ago in the POURING rain. We put on our ponchos and did EVERYTHING! Yes, we were soaked by the end of the night, but we got to do all the rides, I don't believe any were closed due to just rain, if there had been thunder or lightning in the area, I'm sure that would have been different. Needless to say, we had a blast, and we have the funniest picture from the night, the two of us in our yellow ponchos with those bucket-style rain hats on.
I don't know if the parades were cancelled, I'm going to go out on a limb and guess they were, the weather really was pretty bad.
BUT as we were leaving the park, a nice CM with a clipboard stopped us and asked us if we had had a nice time. We said we did, despite the weather, and she smiled and handed us a square business card with an address on it. She said to send our tickets from the party to that address and we would be "compensated." I didn't know if they were refunding money or what, but about two weeks later, we received two one-day park hoppers in the mail with a note that said something like "Glad you had a great time, now enjoy a SUNNY time on us!"
It was a little bit of pixie dust and very unnecessary and unexpected!