MishaXWhen bags are rated pretty true to their actual warmth, I usually match that well. I had one of these for a time and found it good to about 50F wearing undies and sometimes a t-shirt. It's a little tight in shoulder room but not a bad summer choice. It'll cost you four times as much, but a good Climashield Apex summer quilt is the way to go for summer, imho. Much more room, easy venting, tailor the sizing to your liking, and you'll drop at least 10oz.