A sleeping bag needs to suit the night as well as the boot. For two camping nights by Lake Siljan, I would start with the expected overnight temperature and the space I need to turn over.
Read the comfort rating first
One sleeping bag may show comfort, limit and extreme ratings. These describe different test conditions, not three equivalent promises of comfortable sleep. The Swedish Scouts explain the ratings and recommend choosing for the seasons when you actually intend to use the bag.
I would compare comfort ratings and the manufacturer's advice for the intended use. The extreme rating is not a target for a comfortable camping night. If you tend to feel cold, allow for that when choosing; a laboratory rating cannot predict exactly how you will sleep.
Consider this example: the forecast is 5°C, and two bags have comfort ratings of 10°C and 0°C. I would not choose the bag marked 10 just because it packs smaller. This illustrates how to read the label, not a safe temperature threshold for every person.
Try the fit with the zip closed
Get inside. Close the bag. Turn onto your side and check whether your shoulders, knees and feet have room without forcing your posture.
Read the recommended user height rather than just the bag's external dimensions. Try opening the zip from inside and adjusting the hood if it has one. I would spend a few minutes on that test before choosing by colour or the words “three season”.
Match packed size to how far you will carry it
A bag carried from car to tent need not be chosen like one carried all day. For the Siljan weekend, I would first check that the bag, mat and dry clothes fit together in the car. If the same bag will come hiking, its weight and packed volume also need to work in your rucksack.
Filling material alone does not decide which bag suits you. Compare the finished model's temperature rating, dimensions, care instructions and price. Borrow a suitable bag for a trial night if you can before buying your own.
Try the whole sleeping setup before leaving
Lay the bag on the mat you plan to take. A spacious bag is little help if the mat is too narrow or lacks insulation for the conditions. Our guide to choosing a sleeping pad for warmth and space covers that part.
A trial night close to home lets you stop if the equipment is inadequate. I would do that before a longer trip and pack sleeping gear so it stays dry in transit.
Keep the place you want to revisit
After two nights by Siljan, the evening photo from your first stop may be the one you want to keep. FARON can hold the photo and overnight stay together on your map. Log your first night with the location and your own note.
Frequently asked questions
Should I choose by the extreme rating?
No. Do not use it as a target for a comfortable night; compare comfort ratings and manufacturer guidance.
Is a three-season label enough?
No. Read the model's temperature ratings and choose for your intended conditions.
Is the smallest packed size always best?
No. For car camping, fit and suitable warmth may matter more than saving a few litres in the boot.
What should I try before the trip?
Try the sleeping bag and mat together, including the zip, your sleeping position and the available space.
