What temperature sleeping bag for summer use?

[KnifeStyle]

I'm replacing a three season bag I lost in a flood, which at the time was a gift and I didn't have any input on it. I'm currently using a Walmart special for summer car camping and to store in my car, but this one would be stored properly under my bed as real camping gear which may also see backpacking use eventually. But for now, I'm looking at using it in civilized campgrounds in a tent next to my car using a Thermarest. If I play Survivor Man and get a twenty degree bag, am I going to be roasting all summer? If I get a light summer bag, will I be miserable layering up if we do anything in early fall or late spring? I'm looking to balance out the worst case scenario without lugging around a huge bag or fighting a small one. I currently do now own a ruck and live in Illinois, backpacking is a major what if because it's not easily accessible in this area.

[Confucius]

All depends on where you're going to be using it. I use a 20 degree down bag for my summer backpacking, but that's just because I do most of my summer backpacking in the sierras, where even in the height of summer, 30 F nights aren't super uncommon.

I'd rather be too warm and have to stick a leg out from the bag to cool down than be too cold...

[Boondock]

I use a USGI poncho liner in the summer. Works great.

[majorhavoc]

All depends on where you're going to be using it. I use a 20 degree down bag for my summer backpacking, but that's just because I do most of my summer backpacking in the sierras, where even in the height of summer, 30 F nights aren't super uncommon.

I'd rather be too warm and have to stick a leg out from the bag to cool down than be too cold...

This. Here in New England, summer camping in Acadia or some of the White Mtn National campgrounds means the possibility of overnight temps dipping into the high 30's.

FWIW, at any given temperature rating, I've found that sleeping bags insulated with natural down seem to have a wider comfort range than synthetic fill.

[Woods Walker]

I use a poncho liner mostly in summer or my UL downbag. Honestly a 20 degree bag is overkill (but that depends on local conditions) however it's a good jack of all trades. You can use it as a blanket in warmer weather.

[Dragon80]

I agree with Major and Woods Walker. On insulation, down is just better but go for the Dri Down, it can get wet and not be ruined.

I personally use a Kifaru Woobie and living in Indiana, it can go from 50 degrees one night to 70 the next as a low and a few weeks ago on my last trip, I was roasting in it until a major storm pushed through and the temps dropped to the low 60's with 40+ MPH winds, then I was comfortable. lol

[KnifeStyle]

Currently, my price range and dedication level only allows for synthetic bags. That should highlight the focus between lightweight synthetic and mid-weight synthetic.

[olbaid_dratsab]

HPG Mountain serape for me almost exclusively. I've used it in snow, 10-20degrees, coupled with a poncho a bunch of times. Its sucky cold, but so much faster then ripping a bag from a stuff sack. Also I was fully clothed, no sleeping mat. Yeah for sleeping a bag is better in cold, but you're talking about summer anyway.

In the summer, I use it in great coat mode. Allows me to keep my boots on and sleep comfortably. With the hood and "sleeves", it sort of keeps you covered better than a bag and is easier to role over in. Yet, its still easier to breath out of. Its in my top 10 favorite pieces of kit.