Well, I live in Sunny South Florida, Ft. Lauderdale area, and it's HHHHOOOOTTT! The sun it hot around 8:30am and it does not began to cool until 6:30 or 7pm. The temp is around 90 to 94 degrees. I cycle for 4,5,or 6 hours. I always freeze 5 water bottles, take three with me, two on the bike and wrap one in plastice(keep things from getting wet) and place it in my tail rider trunk bag. This seems to carry me through. It's best if you let the water freeze for a couple of days, rather than overnight. This is why I freeze five, the other two will be solid when I'm ready for them the next day.