Sleeping Bag Temperature Ratings Explained: Don’t Get Caught Cold

A “30°F sleeping bag” doesn’t mean you’ll be comfortable at 30°F. Temperature ratings are confusing by design. Here’s what they actually mean and how to choose the right bag.

The Three Ratings

Comfort Rating

The temperature at which an average cold sleeper will be comfortable. This is the number to trust. Our 3-season sleeping bag has a 32°F comfort rating — good for spring through fall.

Lower Limit

The temperature at which an average warm sleeper will still be comfortable. Typically 10-15°F below comfort rating. Use this only if you naturally sleep warm.

Extreme Rating

The temperature at which you’ll survive but be miserable. Never plan for this number — it’s a survival rating, not a comfort rating.

Choosing Your Rating

• Summer camping (above 50°F): 40-50°F rated bag
• 3-season (spring/fall, 25-50°F): 20-32°F rated bag
• Winter (below 25°F): 0-15°F rated bag

Pro Tips

• Buy 10°F colder than you think you need — you can always unzip
• A sleeping pad matters as much as the bag — cold ground steals heat
• Women should add 10°F to ratings (women sleep colder on average)

Shop all camping gear.

Comfort vs Lower Limit

A bag rated to 20F means you’ll survive — not that you’ll be comfortable. Buy a bag rated 10-15F lower than the coldest expected temperature.

Insulation Types

Down: Best warmth-to-weight. Compresses small. Loses insulation when wet. Measured in fill power — 650 good, 800+ premium.

Synthetic: Retains warmth when wet. Dries faster. Costs less. Heavier and bulkier. 3-5 year lifespan.

Shape Matters

• Mummy — Most thermally efficient, snug fit, best for cold weather
• Rectangular — Most spacious, less efficient, best for car camping
• Semi-rectangular — Good compromise between warmth and room

Don’t Forget Your Pad

Sleeping bag insulation compresses beneath you, providing almost zero warmth from below. Your pad’s R-value matters equally — R3+ for 3-season, R5+ for winter.