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How does one calculate the warmth of a jacket?

I am looking at getting a new jacket, but find the warmth descriptions vague. If a jacket is listed as "warm," in the product description, what does that mean?

11 Replies

Not very meaningful....I don't know of any standard for clothing like that used for sleeping bags.  "warmth" is quite variable, depending upon your exertion level, other clothing worn, diet, etc....

This is one reason layers are recommended. you can adjust, depending on conditions.

Superusers do not speak on behalf of REI and may have received
one or more gifts or other benefits from the co-op.

I second the layers approach.  Generally everything that is listed as a "shell" jacket is just that, blocks rain, wind, and/or snow, but usually isn't insulated.  The insulated jackets will sometimes list the weight of the insulation, so if you have ever worn something like this in the past you can compare.  Not all insulation is the same though, each has different thermal property per weight (down, synthetic down, thinsulate, polartec, etc. a gram of one doesn't equal the warmth property of any other).

Try them out, compare, return the ones to REI that don't work for you.  It's really hard to say without testing for your conditions and activities.  When I cross country ski, I may be in a T-shirt even though it is below freezing because of how much heat it produces, but if I was sitting down outside watch something at a venue at the same temperature I may need my synthetic down jacket with two layers underneath.  When downhill skiing I need my windproof/snowproof shell at a minimum and can add layers under that depending on the conditions (thin puffer, 2-3 layers merino, etc.).  Hope that helps!

Superusers do not speak on behalf of REI and may have received
one or more gifts or other benefits from the co-op.

As indicated, layers are important.  I would also suggest to talk to the staff at the store, if you can.  I purchased my last winter coat after discussing my requirements (warm, rain-proof, light-weight) to the salesperson and they took me right to the jacket that I purchased and have enjoyed. 

Superusers do not speak on behalf of REI and may have received
one or more gifts or other benefits from the co-op.

@davidbrownlawman, this is such a great question, sadly there is seems to be no good answer.

Like @hikermor  @Joe  @Diesseldorf previously said, layers and experience are your best bet.

I go through this dilemma every time I get cold. You have Everest base camp down body parkas on one end and a sweater overlayed by a rain/wind proof shell on the other.

For my region's normal coldest winters, range ~ +5f and up, I'll wear a base thermal long sleeve either nylon or polypro, a thick(er) pull over shirt, a really thick sweater, e.g. the NF Denali, a 800-900fill down jacket, all overlayed with my NF rain jacket, then strip off as needed.

This mainly applies to times not hiking or in my bag.

Unfortunately, the worst times are when arriving at camp, eating and the coldest being around breakfast.

I've heard that good decisions come from wisdom, which come from experience, which comes from bad decisions. lol.

practice, practice, practice!

good luck

REI Member Since 1979

forgot to add, really thick, military grade, bottom thermals, usually too warm to hike in.

My buddy has a set down pants he puts over everything at camp.

And a super thick balaclava to wear for sleeping.

stocking caps should all come with some sort of strap to keep it on your head at night, like those peruvian style hats.

REI Member Since 1979

i agree with @Diesseldorf on using the retailer's return policy (REI has a nice return policy).  The fun is that rating system (like the EN/SIO for sleeping bags) do not tell you how it will work for you.  The truly nice thing with rating systems (like that EN/ISO) is that it allows us to compare manufacturers.  I sleep cold and that can bother me in the Sleeping bag.  It would be nice if there was a rating system just to be able to compare products from different manufacturers.

My gear (and it is only my gear, opinion and what has worked for the trips so far).  is a bit smaller.  I do not have a jacket.  I have if really cold used my coat which is similar to Carhartt) which I have also used for car camping and casual use.  As far as backpacking, and I have not been in really cold weather with these items, is my base layer one or both of my (polyester) fleeces (one 1/4 zip The North Face [pretty lightweight] and the other a Columbia full zip [for tall folks]).  And, for wind or rain my Marmot PreCip rain jacket.  That is just what I chose for me and was also what I looked at for my trip to Philmont Scout Ranch (northeast New Mexico).


Doesn't philmont do their thing in the summer?  Always hot during the day, cold at night.

the is from end of May last year

REI Member Since 1979

Yes, Philmont's main treks are in the summer.  the even recently changed the summer to having 12-day, 9-day, 7-day treks (as well as the cavalcade; horseback treks).  The summer treks are by lottery (drawing) and have to have Scouts (youth) in the crew.  And the crew has to choose a trek/itinerary (not sure about the Cavalcade).  there is also for youths a 21-day Rayado.  However, they also do other types of treks in the Fall and Winter.  And at least, the Fall can have an adult only crew.  The fall is one where you can choose what you do.  The winter session is a bit less clear.

Yes, the days can be warm and the nights cold.  I was there around June 25, 2017 for about 13 days.  We arrived a day early and paid for the extra night at base camp and the extra meals in base camp.  Philmont base camp sits at around 6700-6800 feet above sea level.  and depending on your itinerary you could get up over 12,000 feet above sea level.  Our itinerary is no longer offered and was in both the south and north half of Philmont (included Baldy Mountain at about 12,441 feet).  And, we had hail with thunderstorms on the one day.

Philmont had to change some of its itineraries due to the Ute Park fire in 2018 (burned about 27,000 acres in Philmont alone.  I wish Philmont would think about opening up some of the off season (fall winter) to folks who are not or no longer associated with Scouting.

Definitely a nice trip.


@JohnL02thanks, good stuff. Wish I could have gotten out there when I was with a troop.

REI Member Since 1979