where I live, July temps are in the upper 90's (at least) even after the sun goes down. So one really cute idea I've seen was to have the personalized waterbottles (some places will print labels in your colors with your names etc) for each of the guests. But have them displayed in old wine barrels, or the old galvanized washtubs; all filled with ice to keep them cool. These were right next to the guest book so that the guests could have them throughout the wedding.