I have a Igloo 5-Day or something like that. Anyway that's not important. What IS important is I read somewhere about using a "blanket" on top of the ice.
I used the Igloo during a 4-day trip in Central Texas in July. It was outside the whole time but in the shade. This was the cooler we kept our drinks in & I & 3 teen boys kept it opened up plenty. Temps were high 90's during the day & mid-70s at night.
Started with 3 bags of ice & about 30 cans/bottles of pop/water. I bought one of those accordion silver auto shades & cut it to fit tightly inside the cooler. We kept it pushed down on the ice & pop. We had to add warm pop as we drank the cold & added 1 more bag of ice on the 3rd day (morning).
When we got home on the 5th day we still had ice/cold water in the cooler. I will use the "blanket" from now on.