Zero rated sleeping bags
When it came to warmth, features, and overall feel, nothing topped Sea to Summit’s Ascent sleeping bag. We tested the 15-degree bag, but it is also available in zero- and 25-degree versions. While the Ascent’s 750-fill down means it won’t pack down as small as higher-loft bags, Keep in mind that a 700-fill-power down sleeping bag rated +20°F will be lighter than a 600-fill-power down bag rated +20°F. A 3-season sleeping bag normally has a rating of at least 600, but if you are planning on being in sub-zero weather you should be considering 900 to 1000-fill-power.