What Temperature Quilt Do I Need?

A quilt rating is not a promise, and it is the single most over-interpreted number in a sleep system. Two quilts both labeled 20°F can be twelve degrees apart in practice, because one number came out of a laboratory and the other came off a loft chart. So the useful question is not “which rating is best” but “what does my coldest night actually demand, and how much margin am I buying?”

The method, in four steps

1. Find your coldest realistic night. Not the coldest night you can imagine — the coldest night you have actually camped, or will. Look up overnight lows for the elevations and months you hike, then take the lowest one you would still go out in.
2. Subtract about 10°F. That covers the gap between a limit rating and a comfort rating, an untested maker estimate, a wet or windy pitch, and being tired and underfed on day four.
3. Buy the rating that covers the result. If your answer is 28°F, you want a 20°F quilt. If it is 42°F, a 30°F quilt has plenty of margin.
4. Check the pad under it. A quilt has no insulation beneath you at all, so its real-world rating is capped by the pad's R-value. More on that below.

What the rating actually describes

The practical consequence: a tested limit rating needs roughly 10 degrees of margin for a cold sleeper, and an untested rating needs that plus however much you discount the maker. Our temperature ratings guide works through the standards in full.

The three bands, and who each suits

If you are buying one quilt and you do not know yet what your trips look like, buy 20°F. It is the band with the deepest field, you can vent it on a warm night, and you cannot add fifteen degrees to a summer quilt in October.

A quilt at each rating

Four quilts across the three bands, so you can see what each rating costs in grams and money. Every weight and rating here is the maker's own figure, linked in the sources.

The pad decides half of it

This is the part people skip, and it is the usual reason a correctly-rated quilt feels wrong. A sleeping bag has insulation underneath you, compressed and not doing much, but present. A quilt has none. Everything between you and the ground is the pad.

Ground conducts heat out of you roughly twenty times faster than still air, so the pad's R-value sets a ceiling on your whole system. As a working pairing:

• 30°F quilt: R 3 or better. A Therm-a-Rest NeoAir XLite NXT at 370 g (13.1 oz) publishes R 4.5, which is comfortably past that.
• 20°F quilt: R 4.5 or better.
• 15°F quilt or colder: R 5 and up, or stack foam. A Z Lite SOL at 410 g (14.5 oz) publishes R 2.0 and adds to whatever is above it.

Full detail in our R-value guide, and the winter end of the field is on best winter sleeping pads.

If you sleep cold

Some people simply run colder, and it is not a character flaw to plan for it. Four fixes, in order of how much they return per gram:

Only after those four should you buy a colder quilt. A quilt one band colder than you need is typically a few hundred grams and a real amount of money, and the pad fix is usually cheaper.

One quilt or two?

If you hike year-round, two quilts often beat one. A 30°F quilt for summer and a 20°F for shoulder season is lighter on every summer trip than carrying the cold quilt all year, and a summer quilt is the cheapest single way to cut half a kilo from a mid-season kit. The Vesper 32 at 440 g (15.5 oz) against the Vesper 20 at 550 g (1 lb 3.4 oz) is the same quilt in two ratings, and the difference is what you carry all summer for nothing.

If you hike a handful of weekends a year, buy one 20°F quilt and vent it. The second quilt is a weight-optimization purchase, not a comfort one, and it only pays off at volume.

Still deciding between a quilt and a bag at all? Quilt vs sleeping bag covers which suits how you move in your sleep, and the 20-degree quilt ranking is where to go once you have settled on a rating.