Guide 3 min
Which down jacket for which temperature hiking?
0, -5 or -15 C? The right down jacket isn't the warmest, it's the least warm that covers your night. The three tiers, and how to read yours.
0, -5 or -15 °C? The right down jacket isn't the warmest. It's the least warm that covers the night you're actually going to spend. WildKit sorts warmth into three tiers: tier 0 cuts the chill, tier 1 holds down to -5 °C, tier 2 holds down to -15 °C. You take the one that covers your night, not one more.
A down jacket that's too warm doesn't warm you any better: it weighs more and it takes up room. Each kilo costs 5 litres in your bag. Here are the three tiers, how to read the label on yours, and how to work out how low your night will go.
Three warmth tiers, not grams
You don't pick a down jacket by weight, you pick it by warmth. Three tiers cover almost every night:
| Tier | Covers down to | For which night |
|---|---|---|
| Tier 0 | around 0 °C | chill-breaker, mild nights and stops |
| Tier 1 | -5 °C | cool nights, spring through autumn |
| Tier 2 | -15 °C | cold nights, winter or altitude |
On the label, read the rated temperature. A down jacket rated -5 °C (roughly the level of an MT100) is a tier 1. One rated around -10 °C (an MT500, say) is clearly warmer, over towards tier 2.
Your night drops lower than the season
The classic mistake: choosing against the daytime temperature. Your down jacket is what you wear in the evening and the early morning, when it's coldest. And the higher you climb, the further the night falls: reckon on -6 °C for every 1000 metres of altitude.
An example. A spring night rated 0 °C down at low ground drops to -9 °C if you camp at 1500 metres (0 minus 6 times 1.5). -9 °C is below -5: tier 1 no longer holds, you need tier 2. The same trip 1500 metres lower gets by on a tier 1.
Keep the least warm one that covers
Once you know your night, the rule fits in a single sentence: you keep the least warm tier that covers it. Your night stays above -5 °C? Tier 1 is enough. It drops below -5 °C? You step up to tier 2. Never the other way round.
Why not go warmer "to be safe": because it costs you twice. A warmer down jacket is heavier, and each kilo costs 5 litres in your bag (see How much your bag should weigh). You'd be carrying warmth you won't put on, at the price of weight and space.
What the down jacket doesn't replace
A down jacket warms you when you're stopped or walking slowly: at camp, on a break, when you wake up. It isn't your sleep system. Once you're lying down, what cuts you off from the cold is the ground beneath you far more than the layer on top of you (see The sleeping mat makes the cold night). Keep your down jacket for standing still, not for making up for a sleeping bag that's too light.
What to remember
- Three tiers: 0 (chill-breaker), 1 (down to -5 °C), 2 (down to -15 °C). Read the warmth, not the weight.
- Choose against your night, not your day: it loses 6 °C for every 1000 metres of altitude.
- Keep the least warm tier that covers. Warmer means heavier, and 5 litres more bag per kilo.
Your real night depends on your season, your altitude and the number of nights, not on a label read in the shop. Describe your trip in the configurator: it works out the temperature you'll actually face, then suggests the right tier, neither shivering nor needlessly heavy.
A guide WildKit keeps up to date. Published .