The best three-season sleeping bags are essential bits of kit for spring, summer and autumn nights in the great outdoors. Choosing the right bag will help guarantee that you stay warm while camping. Plus, unzipping your tent to enjoy an epic view from the warmth of a cosy sleeping bag is one of life’s great pleasures.
But buying one can be a bewildering task. To help you pick the right bag, think about when and how you’ll use it. Will you be backpacking or car camping? And do you need a bag for warm summer nights, or cooler spring and autumn seasons? Also consider how your sleeping bag works with your pack, tent and sleeping mat. This guide will help you find the best three-season sleeping bag for your needs, with versatile options for different weather conditions.
Sleeping Bag Temperature Ratings Explained
To compare the warmth of different bags, look at their temperature ratings. Many sleeping bag brands use a standard rating. This is usually given as three figures: a comfort, limit and extreme temperature rating. The comfort rating is defined as the temperature at which a ‘standard female’ can sleep comfortably. The limit is the temperature at which a ‘standard male’ will be able to sleep without waking. Extreme is the temperature at which a ‘standard female’ can remain for six hours without risk of hypothermia. It’s not a perfect system, as we all differ in shape, size and how much we feel the cold. The figure you need to consider most is the limit rating. Most of the bags featured here have a limit rating of around -5ºC.
Down Or Synthetic Sleeping Bags?
Weight is another critical factor. The ideal three-season sleeping bag will weigh around a kilo. Weight is largely dictated by the materials used, especially the insulation. This will be either goose or duck down, or a synthetic fill. For its weight, down is the warmest, lightest and most packable option. Its main disadvantage is that if it gets wet, it loses its insulating properties. Synthetic sleeping bags are heavier and bulkier but also cheaper, and they will still insulate when wet. So if you’re on a tight budget or go camping in damp conditions, a synthetic bag is a good choice.
The performance gap between down and synthetic insulation is narrowing, however. Modern down is sometimes treated with a DWR (durable water repellent) that means it still insulates even when wet, while innovations in synthetic insulation are getting closer to mimicking the properties of down, making them lighter and warmer.
Down is comprised of the fine feathers of geese or ducks. It is a natural product that can have ethical concerns, though all the sleeping bags featured here use only responsibly sourced down. Down quality is indicated by fill power (FP). The higher the number, the better quality the down. So a sleeping bag filled with 600FP down will require more down fill to generate the same warmth as a higher quality 800FP bag. That means the 800FP bag will be lighter and more packable – but also more expensive.
The most common sleeping bag for backpacking is a ‘mummy’-style bag. These are designed with a close-fitting hood and footbox to maximise warmth. Your bag should feel snug without being restrictive. Many sleeping bags come in different lengths for taller and shorter campers. Others are cut to fit typical body shapes. There are also dedicated men’s and women’s versions. When it comes to features, look for a full-length zip as well as baffle construction. This means the sleeping bag is filled in sections, which stops the insulation migrating inside the bag and causing ‘cold spots’.