Most people don't arrive at hammock camping with a question. They arrive with a cold night behind them.
That's the useful thing about the problem: it's specific. You were warm when you got in, and at some point you weren't. Everything below is written around that.
Start here: it's two jobs, not one
A sleeping bag is built on the assumption that something else — a mattress, a pad, the ground — is handling your underside. A hammock removes that assumption. You are suspended in air on both sides, which makes insulation above you and insulation below you two separate problems.
Top quilt, underquilt. Two planes. Solve them separately, or you will keep solving the same one twice.
- How To Stay Warm Hammock Camping — the whole argument, at length.
- Hammock Gear: What Do I Need? — the short list, before you buy the long one.
- How To Get A Warmer Night's Sleep — what to change when the gear is already right.
Why the bottom is the hard half
Three things happen underneath a hammock, and not one of them needs bad weather.
Compression. Your body weight crushes insulation flat beneath you. Down squashed to nothing doesn't insulate, because there's no loft left to hold air. A sleeping bag underneath you is mostly a groundsheet.
Convection cooling. Air warmed against the underside of your hammock rises away, colder air moves in behind it, and that cycle runs all night. Still air does this on its own. Wind speeds it up — wind is not required.
A slowing metabolism. You make less heat at 3 a.m. than you did at bedtime. That's how a mild evening becomes a cold night: the temperature didn't have to move much, because you did.
Together they explain the thing that catches people out. Nighttime temperatures can be in the 70s and you can still feel chilly.
- Hammock underquilt, do you need one? — short answer here, longer answer there.
- Hammock Underquilt vs. Sleeping Pad — which keeps you warmer in a hammock.
- A Hammock with a Built-In Underquilt — before you buy the all-in-one.
- Hammock Nesting Tricks From an Old Coot — "remedying the problem is a pain at 3 AM if your underquilt is not already attached."
Picking a number
Our ratings are comfort ratings. A 40° quilt is comfortable at 40°F — that is where it is still working, not where it quits.
So the decision isn't really about your average night. It's about your worst one.
And here is the part that surprises people: you cannot overheat from an underquilt. It hangs beneath you rather than on you, and if it's warmer than you need, you vent from above. Which means when you're stuck between two ratings, size up. The mistake only costs you in one direction.
- Hammock Underquilt Temperature Guide — how to pick 40°, 20° or 0°F.
- The Best Hammock Underquilts for 2026 — a buying guide.
Hanging it so it actually works
An underquilt that's snug in some places and gaping in others is doing about half its job. Cold gaps are a setup problem, not a gear problem, and they are the single most common reason a correctly-rated quilt disappoints somebody.
Two things worth knowing before your first hang. Suspension attaches six to twelve inches from the end of the hammock. And dedicated underquilts hang black side to the hammock — on the Dark Olive and Orange quilts, the orange side faces the hammock.
- How to Hang a Hammock Underquilt (and Fix Cold Gaps) — setup, start to finish.
- Hammock Underquilt Fit by Hammock — ENO, Hennessy and Warbonnet.
The tarp
Insulation handles the cold. The tarp handles everything else, and it is the piece people most often buy twice.
- Best Hammock Tarps for 2026 — a buying guide.
- A Few Words About Tarps — rather more than a few.
If you're on the ground
Most of the above stops applying the moment you have a pad under you — the compression problem is what a pad exists to solve. The quilt argument, though, survives the move.
- The Best Sleeping Bag Is A Camping Quilt — the case for leaving the bag at home.
- Best Backpacking Quilts (2026 Buying Guide) — for sleeping on the ground.
- How to Attach a Quilt to Your Sleeping Pad — also for the ground. Fewer drafts.
We invented the hammock underquilt in 2004 and have been sewing them in the USA ever since, which means most of what's written above was learned the slow way. You're welcome to have it the fast way.