Arc'teryx Thorium AR is my top pick.
As most of you know, I've publishing in depth guides to Arc'teryx's and Patagonia's best down jackets for the last couple of years (see full list at the bottom of this post).
Having said that, I noticed that most of you guys also search for recommendations on other brands and models as well using the search button at the top of my sidebar.
As well as searching for "best down jackets"...
...especially for their temperature ratings.
So I thought that putting together a data sheet that lays out all down jackets out in the market can be helpful for most of you when deciding.
Do make sure checking out the given temperature ratings, but still, for most of you...
My number one recommendations would be from my favorite brand Arc'teryx. Thorium AR (Men's - Women's - read my review) would be my top pick, with Cerium LT (Men's - Women's - read my review) being the top alternative to it.
- I also recommend these two as best down picks for casual use out in variable temperature & variable weather, as you can see in my Best Arc'teryx Jackets post.
- Read my Thorium AR vs Cerium LT comparison here.
- Cerium LT also offers alternatives: SL and SV. See my Cerium SL vs LT vs SV post to find out how they compare.
My top non-Arc'teryx pick would be Feathered Friends Eos (Men's - Women's), with Patagonia's Down Sweater (Men's - Women's - read my review) being the top alternative to it.
#Important note: A down jacket will lose its insulating capability under fairly wet conditions. Either from your sweat or wet weather.
That's why, if you're going to be using them in damp areas, I'd urge you to consider getting a synthetic insulated jacket instead. They're mostly heavier, but perform better in wet conditions.
Now let's get to the temperature ratings.
Temperature Ratings
The warmth data provided below for each product are obtained either by:
- Trying them out,
- Analyzing them scientifically,
- And/or gathering tens of authentic, non-biased offline user experience.
Approximate lowest temperatures you can wear each down jacket in the market without feeling uncomfortably cold are...
| °F / °C | Fill Power | Fill Weight (grams) | FP x FW | Face Fabric |
|
|---|---|---|---|---|---|---|
Arc'teryx Ceres SV (Men's) | -15/-26 | 850 | 240 | 204,000 | Arato 30 | |
-10/-23 | 850 | 225 | 191,250 | Arato 7 & 10 | ||
-5/-20 | 800 | 227 | 181,600 | Perfex Quantum Pro |
| |
-5/-20 | 850 | 162 | 137,700 | Arato 7 & 10 | ||
-2/-19 | 700 | 280 | 196,000 | Drilite Loft 40D |
| |
3/-16 | 800 | 182 | 145,600 | Perfex Quantum Pro |
| |
5/-15 | 700 | 179 | 125,300 | Drilite Loft 20D |
| |
7/-14 | 750 | 140 | 105,000 | Perfex Quantum |
| |
8/-13 | 900 | 105 | 94,500 | Perfex Quantum |
| |
8/-13 | 750 | 130 | 97,500 | Arato 30 | ||
12/-11 | 700 | 141 | 98,700 | 3.6 oz 50D polyester | ||
14/-10 | 600 | 177 | 106,200 | 1.4 oz 30D polyester | ||
14/-10 | 850 | 120 | 102,000 | Pertex mini ripstop nylon |
| |
16/-9 | 700 | 133 | 93,100 | 30D Ripstop Nylon |
| |
17/-8 | 850 | 102 | 86,700 | Arato 10 | ||
19/-7 | 800 | 104 | 83,200 | 1.4 oz 20x30D polyester | ||
26/-3 | 700 | 109 | 76,300 | 2.2 oz polyester | ||
26/-3 | 650 | 116 | 75,400 | 20D ripstop nylon |
| |
28/-2 | 800 | 85 | 68,000 | 10D ripstop nylon |
| |
30/-1 | 800 | 81 | 64,800 | 10D nylon |
| |
Marmot Ares (Men's) | 32/0 | 600 | 102 | 61,200 | 1.2 & 1.8 oz polyester |
|
40/5 | 850 | 52 | 44,200 | Arato 7 |
As you see, there's a strong correlation between FP x FW and temperature ratings, but not more than, say, 80%. I explained why this happens here in this post of mine.
These are only approximate values assuming:
- you only have a shirt under and no shell over,
- during daily use (strolls, power walks etc at most - no high output activities),
- with enough wind to cause an umbrella to twist in your hand,
- and when it's dry out.
If you think you run warmer or colder than the average person, then shift temperature ranges accordingly.
As you see, there's a strong correlation between FP x FW and temperature ratings, but not more than, say, 80%.
Let's clarify the reasons behind this.
Warmth
Warmth is the most important thing you should focus on when getting a down jacket. There are two major factors to it:
- Fill power,
- Fill weight.
Note that these are major two factors, not only two factors.
Fill Power
The word "down" is typically mostly referred to as "fill" in down insulated garment language.
Fill Power refers to the fully expanded end volume of a 1 oz down (goose or duck). It's in cubic inches.
For example, a 800 FP (fill power) down will end up getting as large as 800 cubic inches when it's fully expanded at rest.
Because the insulation occurs by trapping air within the vacant spots of down, followed by having that air heated using our body heat.
So, the higher the volume of trapped air (which is determined by the Fill Power of down), the more air will be heated & work as insulation as a result.
In the end, more warmth will be provided.
By the way...
Fill power isn't only about warmth level at all. Having said that, all I'm currently trying to accomplish is to decode the nature of warmth in an analytical way.
Fill Power.
This is why I'm going to skip other roles of fill power and will get back to it later in this post.
Here's a video that also does a good job explaining fill power:
Moving on to our other major factor...
Fill Weight
Fill weight is the amount of down the insulated piece is equipped with. It's just as important as fill power when it comes to warmth.
Because, just like fill power, also fill weight directly affects the amount of air trapped within the vacant spots of down.
That said, the role of fill power on other factors (long term warmth, warmth during movement, warmth distribution, compressibility) is significantly greater than fill weight.
Important: Warmth Calculation
Reminder: Fill power and fill weight are the two most important factors when it comes to warmth.
On a larger scale, assuming both jackets are equipped with identical synthetic insulation (or none of it), it is possible to make very close estimations by multiplying them when comparing warmth ratings of two different pieces.
For example...
- Rab Neutrino Pro offers 227 grams of 800 FP down.
- 227*800 = 181,600
- Outdoor Research Alpine Down offers 182 grams of 800 FP down.
- 182*800 = 145,600
Since 181,600 is significantly greater than 145,600; it's safe to say that the former will be warmer than the latter.
Now...
There are reasons why this mostly won't work on a smaller (or sometimes even on a large) scale.
Comparing two jackets with, say, 125,000 and 120,000 FP * FW values.
The main reasons include but are not limited to:
- Presence of other synthetic insulators,
- Length,
- Bagginess,
- Outer fabric,
- Fill power (I know this is confusing... ignore it for now).
Let's clarify them briefly.
Presence of Other Synthetic Insulators
This is absolutely the most important thing. For example, Arc'teryx always uses synthetic insulation strategically in high wear areas for all their down jackets.
As you can guess, this is part of the reason why they're listed warmer than down jackets with equal FP * FW values.
Length
In colder weather, it becomes much harder to keep your legs and feet warm than your torso and arms.
This is why, the longer the hem length, the warmer the jacket will feel. And the difference is pretty noticeable.
Bagginess
I talked about this more in detail in my Arc'teryx Thorsen vs Therme vs Camosun post.
Baggier cut of Cerium SV helps with its incredible warmth.
Briefly, the amount of trapped air increases as the jacket gets baggier. So more air works as insulation, and ultimately you're kept warmer.
There certainly is something as "too baggy", though. After some point, more inner volume only holds the warmth back.
Weather Resistance & Outer Fabric
Outer fabric is actually much more about weather resistance, but it also affects warmth a little bit.
As explained earlier, no down jacket is able to offer well weather resistance since they get clumped and loses their loft when they get wet.
This is the case regardless from getting wet through your sweat or weather conditions.
That being said, it's still possible to sort them by their strength. But the difference is minimal here - so much that it might not even be noticeable:
Arato 30 = Perfex Quantum Pro > Perfex Quantum > Arato 10 = Drilite Loft 40D > Arato 7 = Drilite Loft 20D > others.
Other impacts of Fill Power
Higher FP will retain its loft with minimal loss during movement. Whereas a lower quality (which is a lower FP) down will do a poor job with this.
For the sake of simplicity and trying not to make this a scientific article, I decided to place equal importance (weight) on fill power and fill weight when calculating FP * FW values.
But, in reality, I'd actually place more weight on fill power. Maybe squaring the FP and then multiplying it with FW would be a more accurate calculation to yield better results.
How do down jackets compare to synthetic jackets?
Here's the full data set for Arc'teryx's and Patagonia's almost all insulated garments.
| °F / °C | Insulation |
| Discount Availability |
|---|---|---|---|---|
Arc'teryx LEAF Cold WX Parka SVX (Men's) | -40/-40 | Down |
| |
Arc'teryx Ceres SV (Men's) | -15/-26 | Down | ||
-10/-23 | Down | |||
Arc'teryx Dually Belay Parka (Men's) | -7/-22 | Synthetic |
| |
Arc'teryx Thorsen Parka (Men's) | -7/-22 | Down | ||
-6/-21 | Down | |||
Arc'teryx Centrale (Women's) | -5/-20 | Down | ||
-5/-20 | Down | |||
Arc'teryx Therme Parka (Men's) | -2/-19 | Down | ||
0/-18 | Down | |||
Arc'teryx Camosun Parka (Men's) | 0/-18 | Down | ||
3/-16 | Synthetic |
| ||
3/-16 | Down | |||
Arc'teryx Patera Parka (Women's) | 5/-15 | Down | ||
Arc'teryx Kappa (Men's) | 7/-14 | Synthetic |
| |
8/-13 | Synthetic |
| ||
8/-13 | Down | |||
10/-12 | Synthetic | |||
Patagonia Vosque 3-in-1 Parka (Women's) | 10/-12 | Down | ||
12/-11 | Down | |||
14/-10 | Down | |||
Arc'teryx Magnus Coat (Men's) | 14/-10 | Down |
| |
17/-8 | Down | |||
19/-7 | Down | |||
19/-7 | Synthetic | |||
23/-5 | Synthetic | |||
24/-4 | Synthetic | |||
24/-4 | Synthetic | |||
26/-3 | Down |
| ||
28/-2 | Synthetic | |||
32/0 | Synthetic | |||
40/5 | Down | |||
43/6 | Synthetic | |||
50/10 | Synthetic |
Read more about this chart here in my Insulated Outerwear Temperature Ratings Guide.
These are only approximate values assuming:
- you only have a shirt under and no shell over,
- during daily use (strolls, power walks etc at most - no high output activities),
- with enough wind to cause an umbrella to twist in your hand,
- and when it's dry out.
If you think you run warmer or colder than the average person, then shift temperature ranges accordingly.
Also check out my Arc'teryx Favorites and my Patagonia Favorites.
If you're interested in down jackets only, see my Best Down Jackets post.
Lastly, if you're interested in Patagonia only, check out my Best Patagonia Down Jackets post.
I hope this post was helpful for you to learn more about the jacket(s) in your mind.
Feel free to ask me any questions or provide feedback and I'll be happy to respond in the comment section below.
Guide: Insulated & Shell Jackets
Start here:
Complete list:
Thank you for reading!
