Therm-a-Rest may have created the ultimate cold weather sleeping bag. Rated to a limit of -20 degrees F (comfort -4 degrees F), the Polar Ranger sleeping bag is packed with well-thought out features that enable you to sleep comfortably in the most extreme environments.
The Polar Ranger is stuffed with 800-fill Nikwax Hydrophobic Down and uses reflective layers to help trap heat inside. To make it easier to get in and out, the sleeping bag features a half center zip with overstuffed draft tubes to keep any warm air from leaking out. I personally wish every sleeping bag used a center zip.
Similar to the Nemo Canon, the Polar Ranger gives you two zippered arm openings that not only enable you to let out excess heat at night, but coupled with the center zip, allow you to cook and perform other tasks without ever leaving your cozy bag.
The synthetic snorkel hood cuts down on condensation from your breath soaking the top of the bag and chilling your face. From past experience, you don’t want to be claustrophobic if using the snorkel hood but in an extreme temperature situation, I would suck it up just to keep warm. The Polar Ranger also features the Therm-a-Rest Toe-asis — a baffled foot warmer pocket at the bottom of the bag that helps to rapidly warm up cold toes.
While most of us don’t plan to regularly sleep outside in sub-zero temperatures, if you do find yourself camped out near the North Pole or at the South Col of Everest, there are ways you can make the Polar Ranger even warmer — the bag comes with quilt and blanket loops to secure an extra down blanket thrown over the top that will trap warm arm between the two layers. The bag also has SynergyLink Connectors to secure it to your sleeping pad so you don’t lose warmth beneath you either.
In Crested Butte, I had the chance to spend the night in the Polar Ranger. As temperatures dropped in the teens, I was incredibly snug in my sleeping bag wearing just my base layers. I even had to ditch the thick wool socks in the middle of the night.
The new extreme-weather sleeping bag weighs in at 1459g (3 lbs 3 oz) in the regular size. The Therm-a-Rest Polar Ranger will start shipping in the spring.