Grumman jacket temperature limit

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Feb 2, 2020
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I've been interested in the SG Grumman jacket and am wondering what most people find is the lower temperature limit of this jacket when sitting stationary, with light wind (up to 20mph), and only a couple thin layers underneath.
 
If the wind is blowing close to 20 mph you likely won't hit 35 degrees maybe 40 if you are warm blooded and have some extra layers underneath.
 
I cant speak to this exact scenario. However, this late rifle season this year we rode the quads in to a glassing knob and it was low teens when we left the truck, probably mid teens when we got to the knob and we sat there for a good couple hours before spotting some elk. This was an exposed hillside with a modest constant facewind. While i felt the cold, I was not to the point of having to reconsider or think about building a fire.

My layers were: Aerowool T, Kuiu pro merino 200, Kuiu peloton 240 hoodie, Kuiu kenai vest, and finally my SG grumman.

That being said, depending on your definition of "thin" layers; id say you could potentially sit in near freezing to minimally sub freezing temps. The ticket is a wind stopping layer under that puffy to take the bite off.
 
I cant speak to this exact scenario. However, this late rifle season this year we rode the quads in to a glassing knob and it was low teens when we left the truck, probably mid teens when we got to the knob and we sat there for a good couple hours before spotting some elk. This was an exposed hillside with a modest constant facewind. While i felt the cold, I was not to the point of having to reconsider or think about building a fire.

My layers were: Aerowool T, Kuiu pro merino 200, Kuiu peloton 240 hoodie, Kuiu kenai vest, and finally my SG grumman.

That being said, depending on your definition of "thin" layers; id say you could potentially sit in near freezing to minimally sub freezing temps. The ticket is a wind stopping layer under that puffy to take the bite off.

Dang that's a lot of layers! Maybe this jacket isn't quite as warm as I'd thought. I usually like to have a wool baselayer and then a thicker layer, then my down, then my rain jacket if the wind is whipping.
 
Dang that's a lot of layers! Maybe this jacket isn't quite as warm as I'd thought. I usually like to have a wool baselayer and then a thicker layer, then my down, then my rain jacket if the wind is whipping.
It seems like a lot because I like to use a vest and a tee shirt no matter what. If you want the warmest jacket possible and weight isn’t a concern; I’d get the FL chamberlain or one of the other mountaineering style puffies. But for the weight the Grumman is hard to beat.
 
32 deg. Its a nice jacket one of my favorites, but 5.3oz of down and sewn through is not going to be a jacket for well below freezing. If you are trying to get into the 20s or teens and stay warm glassing and at camp, you will likely need more down. I own one, but it won't be coming with me in Oct or Nov. From my experience, with just a base layer or two and the grumman, you'll start to get cold in the 20s if you are stationary for long.

If you go to backpackinglight forum you can search thermo-neutral camp chores and some guy on there has a calculation (whatever a "Clo" is...) and real world data on tested jackets. You can find a similar fill weight/power to the grumman and go from there.
 
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It seems like a lot because I like to use a vest and a tee shirt no matter what. If you want the warmest jacket possible and weight isn’t a concern; I’d get the FL chamberlain or one of the other mountaineering style puffies. But for the weight the Grumman is hard to beat.

I was also thinking of the Western mountaineering flight or vapor or meltdown. Or the FF Helio.

I was hoping for something super warm 16oz or under. The Grumman would be the solution if it had a few more ounces of fill. I was thinking it may be borderline for the temps I want it for
 
32 deg. Its a nice jacket one of my favorites, but 5.3oz of down and sewn through is not going to be a jacket for well below freezing. If you are trying to get into the 20s or teens and stay warm glassing and at camp, you will likely need more down. I own one, but it won't be coming with me in Oct or Nov. From my experience, with just a base layer or two and the grumman, you'll start to get cold in the 20s if you are stationary for long.

If you go to backpackinglight forum you can search thermo-neutral camp chores and some guy on there has a calculation (whatever a "Clo" is...) and real world data on tested jackets. You can find a similar fill weight/power to the grumman and go from there.

Thank for the backpacker forum tip. I have a rab electron with 6.7 oz fill, but it's a size too small 😞 so it's not as warm as should be.
 
Sitka kelvin down ws is very, very good for cold temps and is fairly light and packable. I would not hesitate to wear that in 20° or less with combined layers. It holds body heat in better than anything else I have. Good functional hood and two large mesh inner chest pockets to store or dry stuff in..it is pretty bombproof for cold.
 
Sitka kelvin down ws is very, very good for cold temps and is fairly light and packable. I would not hesitate to wear that in 20° or less with combined layers. It holds body heat in better than anything else I have. Good functional hood and two large mesh inner chest pockets to store or dry stuff in..it is pretty bombproof for cold.

2lbs isn't really "fairly light" for a puffy. That has got to be the heaviest puffy on the market. You can get a super warm puffy and a bomber goretex shell for 32oz.

OP, after buying the grumman, then the alpine, then deciding to keep both, i think the montbell alpine would be a better way to spend $300. 7.6oz of 800 fill, box baffle sewn and 15oz, if you want to be warm in camp in the teens.
 
Yes, my WM down jacket is much lighter but not warmer. 2# is not heavy for me....I guess it is all a matter of perspective.
 
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This season I sat for about 3 hrs in 20deg weather before I had to get up an move. That was with base layer, Kuiu guide coat and Grumman.
There was no wind.
 
I was also thinking of the Western mountaineering flight or vapor or meltdown. Or the FF Helio.

I was hoping for something super warm 16oz or under. The Grumman would be the solution if it had a few more ounces of fill. I was thinking it may be borderline for the temps I want it for
Montbell Alpine
 
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