Hot weather tips!
This is an "upgrade" to the washcloth topic. The night before going to the parks, take a washcloth, moisten it (wet, but not soggy), fold it in quarters, put it in a ziplock sandwich bag, and FREEZE IT. The next morning it goes into an insulated lunch bag (small one, just big enough for a couple of sandwiches, get one at teh dollar store) and into my backpack. The frozen cloth feels DELUXE on your neck, arms, whatever around 2pm in the July sun!
I also freeze water bottles. The night before going to the park, each water bottle is half-filled and put in the freezer. The next morning I fill the frozen bottle and stick it in the backpack. The ice melts slowly (sometimes...) and keeps the water very cold for quite awhile (depends on the time of year).
Juice pouches (like capri sun) freeze nicely also, and stay cold for quite awhile as the drink becomes slush, then liquid.
Finally- I always pack a soft-sided cooler, the 6-pack size, in my suitcase. In Florida I put a ziplock of ice into the cooler and a cold drink for each of us, and stick it in the trunk of the car. It stays there until we leave the park and return to the car, with a frosty cold drink for each- SO refreshing when you are hot and tired!
Hmmm...maybe I should change my name to "Freezer Queen"!!