To choose the right temperature, always base your purchase on the coldest temperature to expect during your trip.
If you’re um-ing and ah-ing over what the weather may or may not do, err on the safe side. Temperature expected to be 5 degrees? Go for 0.
It’s a lot harder to increase your warmth than it is to cool down. In short, you should always aim to choose a sleeping bag in the Comfort or Transition ranges depending on your individual needs.
How to choose a sleeping bag shape
Sleeping bags come in mummy, semi-rectangular or rectangular shapes. All come with distinct benefits.
Mummy sleeping bags
Core feature: maximum insulation + minimum volume and weight.
The mummy shape is narrow at the feet and tighter around your body so there’s less space around you. This is a deliberate design decision — with less empty space to heat up, your body won’t have to work as hard to stay warm. You’ll stay warmer for longer and use up less energy.
A mummy bag also has a snug hood you can pull around your head for extra heat retention.