Three-season sleeping bags

AA THREE-SEASON SLEEPING BAG is generally thought to be suitable for spring, summer and autumn use. That period covers a huge range of temperatures from well below zero to well into double figures. Designing a product to cope with this is quite difficult. In fact, many sleeping bags termed three-season are too hot for summer unless you are a really cold sleeper, and are actually two-season ones – spring and autumn – while for others the three seasons in question are autumn, winter and spring. It’s easy to increase the warmth of a bag by wearing insulating clothing in it. It’s not so easy to cool down if the bag is too hot.

For comfort over a wide range of temperatures a sleeping bag needs ventilation options. At the very least this should mean a long zip so the bag can be opened up and used as a quilt. Ideally this should be a two-way zip so the foot end can be opened for ventilation and, if necessary, your hot feet stuck out. More sophisticated are bags with zipped panels that can be opened for more room, which as well as comfort means less warmth, or zips both sides so the top can be opened up. One unusual bag has no zips at all but a fold-over section at the top and a slot for your feet.

For cold nights bags need to have a hood that can be closed round the head, insulated baffles behind zips, a shaped foot, and a construction without sewn-through seams – all the bags reviewed have these.

NOTES: The weight is without stuffsacks. All bags weighed on my digital scales. The temperature ratings are those provided by the company. I’ve not been able to try most of the bags at the lowest rating as testing has been