Western Mountaineering summer bags are very light, but too expensive, and a little warm for a hot night. Any summer sleeping bag that weighs more than 2 pounds would be for sure excluded for me as severe overkill. Beyond that, anything might do.

When night time low temperature don't fall below say, 50 or 60 degrees, which is fairly typical in eastern U.S. summertime, have sometimes brought lightweight long underwear, clean and fairly thick socks, a knit hat and a light pile jacket, and no sleeping bag.

The weight of this clothing is perhaps a pound, is adequately warm, and of course is more versatile than a sleeping bag.

Once, I took a bed sheet, but my extra clothing that particular night happened to be inadequate.

In doing this, more times than not, I've slept inside a sleeping bag cover, which is essentially a bivvy sack that has a water-resistant rather than goretex top, and a water-proof floor. It weighs a pound, adds warmth etc., and when folded up requires very little pack space. This addresses the desire to cover self with something while sleeping.

If nothing else, the approach saves wear and tear on the Western Mteering bag for colder nights, and my girlfriend can use my ratty old 'duck down & feathers" summer sleeping bag.

Next week I may do a little camping but don't have access to most of my gear. The girl friend would use WM bag and I'd take a light blanket in addition to above clothing (Might get frost).