Quick verdict
The Arc'teryx Cerium is a premium down insulated jacket built for maximum warmth for its weight in cold, dry conditions, the jacket you pull on when you stop moving, not a waterproof. For most people the standard Cerium Hoody (around £350, 338g, 850 fill-power down) is the one to buy: warm, light and tough enough for real use. The Cerium SL Hoody (around £400, 234g, 1000 fill-power) is the ultralight specialist for counting grams. The standard Cerium also comes as a hoodless Jacket and a Vest, in men's and women's fits; the SL is a hoody only. Down gives the best warmth-to-weight there is, but it struggles when wet, so the Cerium is a cold-and-dry layer that goes under a shell when the rain comes.
Arc'teryx Cerium Hoody: 4.7/5
The do-everything down jacket and the one most people should buy. 850 fill-power down with a tougher 15D Arato shell and synthetic insulation in the damp-prone zones, so it is light and warm without being as fragile as the ultralight SL. Superb warmth for the weight on cold, dry days.
- Ultralight specialist: Arc'teryx Cerium SL Hoody (~£400)
The full review is below.
The Arc'teryx Cerium is a premium down insulated jacket, built for maximum warmth for its weight in cold, dry conditions, the jacket you pull on the moment you stop moving. If you have landed here, you already know you want down. The decision left is which Cerium, because Arc'teryx sells it in two weights and three body styles, and the names do not make the choice obvious.
The good news is that the decision is simpler than it looks. One of them is the sensible default for almost everyone, and the other is a specialist you buy on purpose. This guide settles it, then covers the jacket and vest forms and the women's range.
Which Arc'teryx Cerium should you buy?
For most people, the standard Cerium Hoody is the one to buy. It uses 850 fill-power down with a tougher 15D Arato shell, and it places synthetic insulation in the zones that get damp, so it is warm, genuinely light and far more usable day to day than its featherweight sibling. One down jacket for cold mornings, camp, belays and winter dog walks, this is it.
Buy the Cerium SL Hoody instead if you count grams for a living. It steps up to 1000 fill-power down in a wafer-thin 10D Pertex shell, dropping to around 234g, the lightest serious warmth Arc'teryx makes. It costs more, and that delicate shell wants looking after, so it is the fast-and-light specialist rather than the everyday pick.
That is the decision. The rest of this page explains why, and covers the other forms.
What the Arc'teryx Cerium actually is
The Cerium is Arc'teryx's down insulated jacket, and down is the important word. Down gives the best warmth-to-weight ratio of any insulation, which is why the Cerium packs away so small and weighs so little for how warm it is. The standard Cerium uses 850 fill-power goose down; the SL steps up to a loftier 1000 fill-power.
What makes the Cerium clever is where Arc'teryx does not use down. Down collapses and stops insulating when it gets wet, so the Cerium places small panels of Coreloft synthetic insulation in the spots most likely to get damp from sweat or weather, the cuffs, collar, shoulders and underarms. You get down's warmth-to-weight where it counts and synthetic reliability where down would let you down.
It is not waterproof, and it is not a jacket for sustained rain. Down and British drizzle are not friends. The Cerium is at its best in cold, dry, lower-output conditions: standing around at camp, a frosty summit stop, a belay, a cold commute. When the weather turns wet, the Cerium goes under a waterproof shell and does its warming from there. Think of it as your warmth layer, not your weather layer.
Arc'teryx Cerium Hoody
The standard Cerium Hoody (~£350) is the flagship and the right call for most buyers. It uses 850 fill-power down, a 15D Arato recycled nylon shell and weighs around 338g. That 15D shell is the quiet hero: tougher than the SL's, so the jacket shrugs off everyday handling, pack straps and the odd brush against rock without you wincing.
This is the one down jacket that covers almost everything. It is warm enough for genuine cold as a standalone piece, light enough to stuff in a pack and forget about, and tough enough that you are not treating it like glassware. For UK hill days, winter camping, frosty starts and cold-weather standing around, the Cerium Hoody is the sensible default, and the SL is the exception you reach for only when weight is everything.
Buy the Cerium Hoody direct at Arc'teryxArc'teryx Cerium SL Hoody
The Cerium SL Hoody (~£400) is the ultralight specialist. SL stands for Superlight, and it earns it: 1000 fill-power down, a gossamer 10D Pertex Quantum shell, and a garment weight of around 234g, over 100g lighter than the standard Hoody and barely there in the pack.
That weight is the whole point, and it is a real achievement. If you are a fast-and-light walker, a long-distance backpacker or a climber weighing every item, the SL gives you serious warmth for almost no weight and packs down to the size of a water bottle. The trade-offs are the price, which is higher than the standard Cerium, and the shell, which is thin enough to demand respect around rough rock and sharp zips.
Buy the SL because you want the lightest warmth there is and you will look after it. Do not buy it as your one knockabout down jacket, because for that job the tougher standard Cerium is both cheaper and more forgiving. Note too that the SL comes as a hoody only; if you want the lighter down in a jacket or vest, it does not exist, and the standard Cerium is your route.
Buy the Cerium SL direct at Arc'teryxArc'teryx Cerium Hoody, Jacket or Vest?
The standard Cerium comes in three body styles, and the choice is about coverage rather than warmth level. (The ultralight SL, remember, is a hoody only.)
The Hoody is the flagship and the warmest, with an insulated hood that makes a real difference around the head and tucks under a shell hood. The Cerium Jacket (~£340) is the same body without the hood, around 38g lighter at 300g, which layers cleanly under a shell that already has its own hood or suits anyone who simply does not want a second one. The Cerium Vest (~£280) drops the sleeves for core-only down warmth at around 200g, ideal over a fleece for high-output days or as a light layer that disappears into a pack.
Women's Arc'teryx Cerium range
The whole Cerium line comes in women's versions, on a women's-specific cut with the same 850 fill-power down (or 1000 in the SL), in all three forms.
- The women's Cerium Hoody (~£350) is the warmer, do-everything down jacket, around 290g.
- The women's Cerium Jacket (~£340) is the same jacket without the hood, around 255g.
- The women's Cerium Vest (~£280) gives core-only down warmth, around 170g.
- The women's Cerium SL Hoody (~£400) is the 1000 fill-power ultralight, around 208g, for counting grams.
Which Arc'teryx Cerium for which walker?
Here is the decision by the sort of walker you are:
- You want one down jacket to do everything: the Cerium Hoody. Warm, light, tough enough for real use. The safe default and the right call for most people.
- You count every gram: the Cerium SL Hoody. The lightest serious warmth Arc'teryx makes, if you will treat the thin shell with care.
- You layer under a shell with its own hood: the hoodless Cerium Jacket, which saves a little weight and bulk.
- You run warm or want warmth that packs tiny: the Cerium Vest, over a fleece for core-only down.
- You need warmth in damp or rough conditions: honestly, consider stepping away from the Cerium to a more weather-tolerant down jacket like the Thorium, covered below. The Cerium is a cold-and-dry specialist.
If you are on the fence, buy the standard Cerium Hoody. It does more jobs, costs less than the SL, and survives real-world handling. The SL is the better buy only when you already know that weight is the thing you care about most.
Whichever you choose, the Cerium is a warmth layer, not a weather layer. A waterproof shell over the top is what turns it into an all-conditions setup, and our Arc'teryx jackets explained hub shows how the shells and insulation pieces fit together.
Arc'teryx Cerium vs Thorium vs Atom
Arc'teryx makes three insulated jackets that people cross-shop, and the difference comes down to the insulation and the job:
- Cerium (down): the lightest, warmest-for-weight option, built for cold, dry, lower-output use. Choose it when warmth-to-weight and pack size matter most and you can keep it dry.
- Thorium (down): also down, but a more rugged, weather-tolerant build with a heavier face fabric and more synthetic in the exposed, high-wear zones. Choose it over the Cerium when conditions are damper or rougher and the Cerium feels too delicate.
- Atom (synthetic): Coreloft synthetic active insulation that breathes, keeps warming when damp and layers through changes in output. Lower warmth-to-weight than down, but far happier in the wet and on the move.
In short: Cerium for light, dry warmth; Thorium for tougher, damper down duty; Atom for active, all-weather insulation. For the wider picture across the whole range, the Arc'teryx jackets explained hub is the place to start.
