Big Agnes Greystone 30°

The Big Agnes Greystone 30° is the lightest, least warm member of the Greystone family — a mummy bag rated to 3 °C comfort and -3 °C limit, aimed at late spring, summer and early autumn rather than frost. At 818 g total weight with 336 g of fill, it is the most packable of the three, though its warmth-to-weight figure (272.7 g per degree) suggests the thinner fill layer trades some margin for the lower bulk compared with its colder siblings. Materials follow the family line: recycled polyester ripstop shell, bluesign certification, PFC-free processing, and a left-side zipper that couples with a matching bag. The insulated collar and draft tube carry over even in this lighter build. It suits summer treks and mountain trips where night temperatures only occasionally dip near freezing — as a year-round bag it is not the right pick; for that, look at the warmer 0° or 20° versions.