Choosing a Sleeping Bag – Complete Guide to Temperature, Materials & Seasons

Choose the right sleeping bag – complete guide

Choosing the right sleeping bag is about understanding where, when and how you will use it. Location, season, packing volume, weight and temperature are crucial factors – and affect everything from material to fit and filling. Here we go through what you need to consider when choosing a sleeping bag for your next adventure.

What should you consider before choosing a sleeping bag?

Think about how you will use the sleeping bag:

Hiking in the mountains? → light & compressible.

Winter tours? → warm and strong insulation.

Hard ground, moisture or daily use? → robust and easy to care for.

Weight and packing volume are often decisive when you are carrying everything on your back. For sledding tours, you can instead prioritize comfort and warmth.

Temperature grading – how it works

How warm a sleeping bag feels depends on the climate and how it is used: cold, humid or dry, and whether you are carrying everything yourself or pulling it in a sled.

To make the choice easier, there is the European standard EN 13537, which provides a common yardstick for temperature classification. Three values are used here:

Comfort

The lowest temperature at which a standardized woman (25 years, 60 kg, 160 cm) can sleep comfortably in a relaxed position.

Limit

The lowest temperature at which a standardized man (25 years, 70 kg, 173 cm) can sleep comfortably in a curled-up position.

Extreme

Here the sleeping bag offers some protection against the cold, but the risk of hypothermia is significant with longer exposure (based on a standard woman in a curled-up position for up to 6 hours).

Thermal balance – what affects how warm you feel in the sleeping bag?

A sleeping bag does not create heat – it retains the heat you produce. How warm you feel in the bag therefore depends on several factors:

Physiology

People with more fat or muscle mass retain heat longer.

Women tend to freeze faster than men due to different fat distribution and blood circulation.

With age, muscle mass and metabolism decrease → less heat production.

A well-trained, rested person is more resistant to cold.

If you have recently eaten, heat production increases.

Heat conduction

The greatest heat loss occurs downwards. Your body weight compresses the insulation under you and reduces its effectiveness. Therefore, a good sleeping pad is absolutely crucial.

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Convection

The more air space in the sleeping bag, the more cold air circulates. A “just right” tight sleeping bag is always warmer than one that is too big.

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Wind effect

Wind and airflow quickly cool the air layer around the sleeping bag. Choose a sleeping spot that is protected from the wind.

Evaporation

The body's sweat production affects how hot you feel. Breathable materials transport moisture away and retain heat.

Seasons and sleeping bag selection

Summer sleeping bag

For warm temperatures

Focus on ventilation and moisture transport