My family went to the zoo last weekend when the weather channel said it would be mostly a nice day. We are all fairly smart so just incase we brought unbrellas should the sky spontaneously fall on us. At one point it did, and we were not some of the many folks who were without umbrellas!
What made you suspect that it might rain?
Pessimism I suppose! Im always anticipating that something may go wrong and rain is one of those things!
It's good that you thought ahead.