Snugpak's performance figures are based on more than four decades of experience and customer feedback. Our comfort figures assume that you sleep in light clothing (in thermal underwear or pajamas) in a tent on a good quality sleeping mat. With this outdoor temperature, most users should be comfortable and sleep well.
Low temperatures mean temperatures at which sleeping bags are used by fit people, with minimal discomfort.
Good sleep is influenced by many factors, m.in. climate, altitude, physical condition and metabolism. When in doubt, stick to a comfortable silhouette.