If it's going to be hot, freeze them beforehand if you can. We were a family of 6 adults and 3 children on a very hot and humid day - we filled the bottom of each stroller up with about a case of frozen bottles and not one CM even blinked. The strollers were heavy to push, but it was worth it. We gave a few away while watching the character show in the hot sun in front of the castle. All I can say, is thank you Disney!