Close banner

Support Outside Online

Love Outside?

Help fund our award-winning journalism with a contribution today.

Contribute to Outside

What temperature sleeping bag do I need for a summer in the Rockies?

I'm planning a hike of the Colorado Trail starting in July. What's the best temperature sleeping bag to buy, and what bag do you recommend? Robin Dillon, Colorado


That will be a great trip. The Colorado Trail stretches almost 500 miles from Denver to Durango. It winds through the Rocky Mountains in Colorado, traversing six wilderness areas and eight mountain ranges at heights of up to 13,334 feet. In fact, most of the time you’ll be 10,000 feet or higher. That means nights can be chilly, especially if you’re still on the trail after mid-August.

Western Mountaineering Alpinlite Super Sleeping Bag

Alpinlite Super Sleeping Bag

That said, it won’t be frigid. If you’re a cold sleeper, a bag rated to 20 degrees would be more than adequate—warm enough for cold nights, but not so toasty you’ll poach when the temps are higher. At the pricier end for a bag such as this you’ll find Feathered Friends estimable Swallow ($349;, rated to 20 degrees with a water-repellent EPIC shell. It weighs just two pounds and is an excellent bag. Western Mountaineering’s Alpinlite Super ($385; weighs just a touch less than the Swallow and offers a little roomier cut than most mummy bags. For something more affordable, REI’s Sub Kilo +20 bag ( sells for $239 but is on sale now for $160. It uses good-quality down, has an excellent polyester shell, and weighs one pound, thirteen ounces.

Otherwise, a bag rated to around 30 degrees should do nicely. I like Marmot’s Arroyo ($249;, an 800-fill down bag that weighs one pound, eleven ounces, uses Marmot’s excellent silicon-finished nylon shell, and has a snug-fitting hood. Or, Mont-Bell’s U.L.SS. Down Hugger #3 ($270; is a super-light (one pound, seven ounces) bag that uses Mont-Bell’s proprietary stretchy shell to gently “hug" you as you sleep. That helps reduce cooling that occurs when you thrash around and force warm air out of the bag. I’m using this Mont-Bell bag on some trips this spring and really like it. Sierra Designs’ Osage ($179; uses slightly less fluffy down and heavier materials; but the result is a 30-degree bag of reasonable cost that still weighs only two pounds, four ounces.

Note that I’ve mentioned all down-fill bags. For a trip such as yours I think that’s the ideal material;—light and warm. One synthetic option is the North Face Cat’s Meow ($169;, which uses Polarguard Delta fill, has a temp rating of 20 degrees, and weighs two pounds, ten ounces.

Check out Outside's picks for Gear of the Year and 400-plus gear reviews in the 2007 Summer Buyer's Guide, on newsstands now.

Support Outside Online

Our mission to inspire readers to get outside has never been more critical. In recent years, Outside Online has reported on groundbreaking research linking time in nature to improved mental and physical health, and we’ve kept you informed about the unprecedented threats to America’s public lands. Our rigorous coverage helps spark important debates about wellness and travel and adventure, and it provides readers an accessible gateway to new outdoor passions. Time outside is essential—and we can help you make the most of it. Making a financial contribution to Outside Online only takes a few minutes and will ensure we can continue supplying the trailblazing, informative journalism that readers like you depend on. We hope you’ll support us. Thank you.

Contribute to Outside
Filed To: Sleeping Bags
Lead Photo: courtesy, Western Mountaineering