I generally hunt more than an hour or two from my house so I use coolers for every trip. I have a Coleman Extreme that is my main cooler. I spent 4 days Antelope hunting in 60-70 degree temps and came home with the same ice in the cooler. I spent 6 days Elk hunting which was a little cooler, but still getting into the low 60's most days and I brought home the same ice I left with. I try and keep the cooler in the shade and I drain any water via the water plug every morning and night, which there generally isn't much. I get that if it sits in direct sun and 100+ for a week it's not going to hold the ice, but who honestly goes hunting when it's a 100+.
my 2 cents,
Trevor