Originally Posted by warbonnetguy
for a snug fit the head end edge needs to be even with your shoulders, but to vent slide that edge up just past the top of your head and a gap should open and allow some heat to escape. it might take a few mins to cool down if you're already overheated, but it should cool off quite a bit that way.
This is the way I used my 3-season Yeti on my trip last weekend. The temp was 60ish. I had no problems with over heating, but I used a sheet on top, and I kicked it off a few times.