Kelvin Aerolite Jacket
Aerolite Collection
Kelvin Aerolite Jacket
Aerolite Collection
Kelvin Aerolite Jacket
Kelvin Aerolite Jacket
Kelvin Aerolite Jacket
Kelvin Aerolite Jacket
Kelvin Aerolite Jacket
Kelvin Aerolite Jacket
Kelvin Aerolite Jacket
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Kelvin Aerolite Jacket

  • Big Game : Optifade Subalpine
(14 Reviews)

In a sea of outdoor specialization, having versatile gear as well is a strength. This lightweight, compressible jacket maximizes warmth while minimizing bulk. Use it for everything from backcountry hunts and off-season scouting trips to everyday life; it slips comfortably under a shell whenever you need an extra shot of warmth. Synthetic PrimaLoft® Gold Insulation with Cross Core™ technology replicates the aesthetics and performance of down insulation, but with warm-when-wet performance.

Product ID: #50256

Sizing Guide

Jacket & Tops Sizing

Size Chest Sleeve
Small 36 - 38" 33"
Medium 39 - 41" 34"
Medium Tall 39 - 41" 36"
Large 42 - 45" 35"
Large Tall 42 - 45" 37"
X-Large 46 - 49" 36"
X-Large Tall 46 - 49" 38"
2XL 50 - 53" 37"
2XL Tall 50 - 53" 39"
3XL 54 - 57" 38"

Pant Sizing (Inches)

Size Waist Reg Tall
30 30" 31"
31 31" 31"
32 32" 31" 33"
33 33" 32" 34"
34 34" 32" 34"
35 35" 32" 34"
36 36" 33" 34.5"
37 37" 33" 34.5"
38 38" 33" 34.5"
40 40" 33"
42 42" 33"
44 44" 33"

Pant Sizing

Size Waist Reg Tall
Small 28 - 30" 31"
Medium 31 - 33" 31" 33"
Large 34 - 37" 32" 34"
X-Large 38 - 41" 32" 34"
2XL 42 - 45" 32" 34"
3XL 46 - 49" 32" 34"

Equinox & Dakota Pant Sizing

Size Waist Reg Tall
30 31" 31"
32 33" 31" 33"
34 35" 32" 34"
36 37" 32" 34"
38 39" 32" 34"
40 41" 32"
42 43" 32"
44 45" 32"

Glove Sizing

Size Palm Circ Length
Medium 8 - 8.5" 7.5 - 8"
Large 9 - 9.5" 8.5 - 9"
X-Large 9.5 - 10" 9 - 9.5"
2XL 10 - 10.5" 9.5 - 10"

Gaiter Sizing

Size Calf Circ Boot Size
M/L 17.5" US 6-10"
L/XL 18.5" US 10-14"

How to Take
Your Measurements


    Bend your elbow and put your hand on your hip. Measure from the center of the back of your neck, along the shoulder and down the elbow to the wrist bone.


    Take measurement under armpits, around fullest part of chest and shoulder blades.


    Measure around where you normally wear your pants, keeping the tape measure a bit loose or putting one finger between your body and the tape measure.

  • 4. INSEAM

    In a standing position,measure from your crotch to where you want your pants to end, breaking at the top of the shoe in the front and just above the heel in the back.

  • 5. GLOVES

    With hand partially closed, measure over the knuckles, around the hand, excluding the thumb.

Fit Guide

SITKA Gear engineers gear with a specific Fit and intended end use in mind. These functional designs provide the user with authentic garments for the right situation.

Fit Descriptions

We can communicate our Fit descriptions in 3 different ways. Keep in mind that each garment will allow for layering in accordance to the garments place in a system and described Fit

  • P/F
  • S/F
  • E/F

    Designed for minimal layering. Whether an early season piece or already insulated this garment fits to prevent inefficiencies in heat retention caused by dead space.


    Designed to accommodate layering for more versatility from early to late season climates.


    Designed for maximum layering in the worst conditions. Cut roomier to accommodate additional layering underneath.

Back to Shopping
  • Weight: 16 oz.

  • Synthetic PrimaLoft® Gold Insulation with Cross Core™ technology replicates the warmth and compressibility of down, but with the benefit of warm-when-wet performance

  • Lightweight insulation (35% recycled) is infused with silica aerogel, a nearly weightless material that’s composed of more than 95% air and acts as additional thermal insulation

  • 20-denier polyester face with durable water repellent finish, 20-denier polyester backer

  • DWR finish resists precipitation and prevents face fabric from wetting out

  • Gusseted stretch cuffs allow for smooth, easy layering and unrestricted shooting

  • Fitted hood provides low-profile warmth and concealment; doesn’t obstruct peripheral vision

  • Deep, zippered chest pocket safely stores your valuables

Product is Standard Fit, designed to be layered for versatility.



Why We Made This

The best thing about synthetic insulation is that it stays warm even in extreme, wet conditions. Until now, that reliability has come at the cost of bulkier and heavier products. The Kelvin Aerolite Jacket harnesses the insulating properties of trapped air to create synthetic insulation that replicates the low-bulk, highly compressible characteristics of down, but with warm-when-wet performance. We designed this go-to, versatile layer to keep you warm when you need it, yet disappear in your pack when you don’t.

Product Comments

14 Reviews
Write a Comment
Gary Strong
Reviewed On 11/23/2021

Wore this on Saskatchewan hunt in temperatures of 2°F to 30°F in a pop up blind to test the layering. Seemed thin and I was skeptical of how warm it would be but I was pleasantly surprised. I layered with two heavyweight wool long johns, the Celsius Midi, Kelvin Aerolite Jacket, and Incinerator Bibs and I was not chilled during my nine hour sit. Would like a little more room in arms as us gun hunters don't need such a tight fit as the bow guys. Great job SITKA!

Reviewed On 11/19/2021

Awesome jacket. Absolutely my go-to piece from now on. It's an outer-layer when it’s cool and a mid-layer when it’s cold. Super compressible. Way warmer than it should be seeing as thin as it is. Relatively silent and not nearly as loud as the Kelvin Lite Jacket.Solid color can be worn anywhere. Warm when wet and I mean wet! Wish it came with a stuff sack and removable hood. Hood although is a good snug fit!

Reviewed On 11/02/2021

Not too impressed with this product I’ve been a long term Sitka fan for a while however this doesn’t live up to the name…. After one hunting trip there is already wear and insulation busting out of the seams. I also washed it according to manufactures spec hand washing it with a down specific detergent rinsing twice and then tumble drying with tennis balls and my jacket has water stains all over it.

Nathan Watt
Reviewed On 10/27/2021

This jacket is extremely packable and lightweight yet keeps me more warm than several other parka style jackets I own. Well worth the money and will be my primary mid-layer for the later hunting season and my outer layer during the early season. The lack of bulk makes this jacket extremely versatile without giving up warmth. Most impressive was how I stayed warm after getting caught out in a rain storm...incredible performance.

Will G
Reviewed On 10/27/2021

The jacket is very warm and made well like all Sitka items, but it is far from the athletic fit that I have grown to expect from Sitka products. I have an athletic build, 185 lbs, 6'1, and this jacket looks like a poncho on me, tons of room around my chest and torso. I ordered my normal size of Large.

Peter Katinic
Reviewed On 10/19/2021

This was a go to piece of clothing on my northern BC Caribou hunt. Lightweight, packable and was kind of magic in that it kept me the perfect comfort level across a wide range of temperatures.
I am 5'9" and 230lbs so on the hefty side and the XL was perfect for me. I am pretty broad chested so have hell of time to get jackets to fit my shoulders right. It does have a more forgiving fit in the arms compared to the Kelvin Lite jacket. I pretty much wear this jacket all the time now including around home.

Reviewed On 10/19/2021

I have the original Kelvin Jacket and the Kelvin Aerolite Jacket. Each has its merits. The Aerolite weighs less, better with wind and more packable. I have hunted wearing both jackets (at different times) in upper 20s and low 30s morning weather and I was warmer in the original Kelvin Jacket which I appreciated when I was static. Also, the original Kelvin Jacket allowed for better breathing and moisture wicking. Overall I prefer the original Kelvin Jacket. For me, a mid-layer, should be warm and moisture wicking. There are other layers for wind/water protection. Since the Aerolite does not breathe as well, I think Sitka thought they could reduce the amount of insulation to retain weight to warmth ratio. This is a great jacket for the minimalist, but I definitely prefer the original Kelvin Jacket.

Reviewed On 10/16/2021

LOVE this piece. I haven’t taken it hunting yet, but I live in Alaska and have worn it in a ton of different conditions so far this fall. From rain and cold to snowing in the 20's. Highs were in the 30's the other day and I wore with a medium weight hoodie for 3-4 hours outside. Did not get cold at all. It’s definitely NOT an active insulation piece though. Get moving too much and you’ll get toasty in a hurry. I am 6’4, 210lbs and I ordered a large initially for every day use. It fits amazing but is a little short and not much room for layering. I’ll keep that as my town jacket and just ordered a second in XLT for hunting. Looking forward to testing it in some harsh conditions 2 weeks from now on a PWS Blacktail deer hunt. I have the Kelvin Down Lite Hoody and the Kelvin Down WS Hoodie. It’s definitely not as warm as those…but the synthetic adds a lot of versatility.

Reviewed On 09/24/2021

I bought this jacket for it’s light weight and packability. I took it on a 5 day backcountry elk hunt and really enjoyed the versatility of the Kelvin Aerolite. I was surprised at how well it worked keeping me warm in a wide range of activity. From hiking, glassing after the sun went down, and even sleeping, the jacket was very comfy and functioned well. We got rained on from a storm that came out of nowhere, and it was still warm and comfortable to wear. It’s a great jacket!

Reviewed On 09/16/2021

This is the perfect puffy jacket. I'm blown away with the warmth to weight ratio. Sitka's attention to detail on this jacket shows. The stretch cuffs slide over my release and fit over a watch while still sealing out the wind. It is warmer than the Kelvin Active Jacket. I'm 5'11" and 185 lbs with a muscular build. I wear a size large in all Sitka tops, and this one fits perfectly with room to layer. I love it so much I got Subalpine and black. The only complaint is it's not silent, but still not loud. I don't think the noise will be an issue for archery elk hunting.

Paul l.
Reviewed On 09/13/2021

Just got back from 10 day elk hunt in Colorado. Temps ranged from 34°F to 44°F for lows and 54°F to 65°F for high. Found myself wearing this jacket just about all the time. So lite and comfortable. Warm with minimal layers. Definitely a great piece of clothing. Sitka did very well with this.

Alan W
Reviewed On 09/06/2021

This is my first piece of Sitka gear and wong be my last. For reference I am 6'3", 215 athletic build and I ordered the XL Tall. It fits me perfectly and the quality is awesome. I was worried when I took it out of the box because it feels pretty thin. But then I put it on and could instantly feel my arms and head getting warm. I have no doubt it will be perfect to throw on while glassing between hikes and keep me warm. The sleeves taper perfectly, have a stretch panel down near the cuff so it easily goes over your hands and wont interfere with my bowstring. The hood is also perfect as it isn't bulky, doesn't block your peripheral vision and works great with or without a hat on. The body is a good length and wont let in drafts while sitting to glass for animals. The Subalpine camo is amazing as well and will work pretty much anywhere. Overall, I am very impressed with this jacket. Will update after season on durability.

Reviewed On 08/07/2021

Just got this jacket and without testing it out yet due to it being August all I can do is give a unboxing review. First thing you notice is it is extremely lite. I mean it. I have shirts that weigh more. Fit is perfect. 5'8", 195 lbs. 45 inch chest. Ordered a large. Im surprised at how quiet it is being kinda like a puffy. Its not fanatic line quiet but I will definitely wear whitetail hunting if needed. I ordered this for archery elk hunting and it will definitely fit into pack for that. I will try to do an update after my elk hunt this September. But if you're on the fence, I would recommend you pull the trigger.

Paul K Lowe
Reviewed On 08/04/2021

Just got this today. The reason for 4 stars is because I haven't tried it in the field yet. But as soon as my archery elk hunt is complete I will give a updated review. So this is a first impression review on quality and fit. 4 stars being the highest. Fit is perfect. Im 5'9 190 pounds with a 45 inch chest. I ordered a large. Build quality is very good, typical sitka. Packs down very small, weight is mind blowing. I have marino base layers that weigh more. And im very surprised that this garment is very quiet for what it is. Nothing like a typical puffy. Not silent, but you could stalk wearing it. Hood fits very well. So without testing in the field yet , I can say this product has no buyers remorse attached to it.

1 of 4
Steven Drake - 06.22.2021

Backcountry Essentials

Steven Drake has logged more time than most backpack hunting in remote mountain ranges and prairie. As we all know, the lessons and niche information we glean from experience is invaluable. Information on layering and camping gear is pretty simple to find – but those small, unpredictable items that are worth their weight in gold in your pack are typically discovered after a bad experience. Through hard-earned mistakes, Steven has dialed in a list of obscure gear that he carries in his pack on every hunt. Here’s his full list...