How long will ice cream last in a cooler on a hot day?

Ice cream will last maybe three to four hours if you pack it perfectly—pre-frozen cooler, block ice, full of ice packs, and kept in the shade. In 90-degree weather, it’s a countdown timer because the temperature difference is huge. After an hour or two, edges soften; after three, it’s soup. For a day trip, use dry ice instead, or just eat it within the first stop.