The curious camper might wonder just how outdoor supplies manufacturers determine a sleeping bag’s temperature rating. In truth, the process differs from company to company. Factors might include the loft, or thickness, of the bag; whether or not it features a hood; amount of air space; insulation material; and integrity of the seams. The process is complicated further because different people are comfortable at different temperatures.
It’s generally agreed that it takes a bit less than 2 inches of insulation to provide warmth and comfort in 30-degree weather. As the temperature drops, even more down or synthetic material is required. A Coleman sleeping bag with a hood, drawstring and impermeable seams could keep someone comfortable in otherwise unbearable temperatures. When winter camping season arrives, there’s really no substitute.