Here in Illinois, it is generally very warm and I would just want a thin sheet to cover up with. Last night was an exception as it got down to 56 F here. I find it harder to cope with heat than with cold and have several liners that I can use with my quilt. I took a microfiber fitted sheet and removed the elastic to make a liner. I put a drawstring in the channel across the bottom and hemmed the top. It works, but this sheet is heavy, close to a pound. Polyester, for some reason is just heavy, but it feels better than nylon. I've also got a 100 wt. fleece bag with no zipper, just a footbox. It's comfortable down to the mid sixties, but heavy and bulky. I've also taken to using a pack towel over my pad to absorb sweat. I've tried a poncho liner, but it is too thin for anything but mild weather. One of the best things that I've tried for cool weather is the military Modular Sleep System green patrol sleeping bag. They are cheap and good down to about 50 F. All of these liners add up to bulk and weight when you are trying not to overheat. Most times, I'll default to my 50 F quilt and the microfiber liner. I don't enjoy sleeping out in warm humid weather. I'd rather be somewhere in the arid west where it cools off at night.