How to Stay Warm in a Hammock

Hammock campers have a name for it: cold butt syndrome. The air moving under you pulls heat away, and your sleeping bag is crushed flat under your body so it does almost nothing.

Why it happens

Insulation works by trapping air. When you lie on a sleeping bag, your weight squeezes the insulation underneath and it stops working. On the ground the dirt is still. In a hammock the breeze carries your heat away all night. Many people start to feel chilly below about 70°F.

Fix 1: An underquilt

An underquilt hangs outside and under the hammock, so your body does not crush it. This is the warmest, most comfortable option and what most experienced hangers use. Match the temperature rating to the coldest night you expect.

Fix 2: A sleeping pad

A closed-cell foam or inflatable pad inside the hammock works and costs less. The downside: pads slide around. Double-layer hammocks have a sleeve that holds the pad in place.

Fix 3: Block the wind

• Pitch your tarp low and close one end toward the wind.
• Hang lower to the ground.
• Pick a site out of valley bottoms, where cold air settles.

Small things that add up

• Wear a warm hat and dry socks to bed.
• Eat a snack with fat before sleeping.
• Use a top quilt instead of a mummy bag. Zipping into a bag inside a hammock is awkward.
• Keep tomorrow's clothes in the foot of your bag so they are warm in the morning.