We built two tools that make it easier to sleep well outside — and to choose the right gear without being fooled by an inflated temperature number.
Two of the questions we hear most are easy to ask and surprisingly hard to answer: “Which underquilt do I need?” and “Is tonight a good night to hang?”
The real answer depends on more than one number on a product page — tonight’s low, how exposed your spot is, how you sleep, what you’re wearing, and what’s over you. So we built two free tools that do that math for you. No login, no fuss. Just honest answers.
1. The Underquilt Calculator — which one do you need?
Try the underquilt calculator →
Tell it how cold tonight will get, how exposed your site is, how you sleep and what you’re wearing — and it suggests the lightest underquilt that will still keep you warm, with an honest margin.
What makes it different: we calculate for comfort, not an inflated “with-topquilt” system number. Some brands only quote a colder rating if you also buy a matching topquilt — crediting the topquilt’s warmth back onto the underquilt. We don’t do that. The calculator also accounts for what most people forget: wind matters more in a hammock (you’re hanging in moving air), and clothing is margin, not a substitute (under you, it gets compressed by your body weight — that’s the underquilt’s job).
2. Hammock Weather — is tonight a good night to hang?
Drop a pin anywhere in the Nordics and we’ll read the sky for you — tonight’s low, the wind, the rain — and translate it into hammock language: is it worth hanging, and exactly which underquilt and tarp to bring. You get a colour (good hang / gear up / rough night), warnings for wind and rain, and a seven-night forecast view so you can find the best night this week.
Behind the scenes it runs the same honest model as the calculator, fed by a real forecast.
Why we built them
Because temperature numbers on sleep systems are confusing — and on underquilts often outright misleading, since there’s no standard for what a “degree” actually means. We think you deserve tools that calculate honestly, explain why, and would rather tell you to pack a bit more margin than let you freeze on the first night.
They’re free, they need no login, and they’ll keep getting better. Use them, share them, and tell us if something feels off.
Want to go deeper on how the ratings actually work? Read our underquilt guide on comfort vs. limit, loft, and fill — everything that actually goes into a temperature number.
