Extend 30 degree bag to 0 degree

15F (warmest in your stated range) would be pretty chilly for me on one z-rest. In fact, last winter I camped using 2 z-rest's on top of each other in about 5F temps and still had a cold back.

Doug said it best in the quilt thread.
1. Have a very good pad. At 0 I take both a ccf and ThermARest.

2. Keep your head warm.

The coat is best worn, but not if the bag will compress the down.

I would replace the bivy with vapor barrier clothes.

Robert,
Since this appears to be your first time out in the conditions you describe and the trip is short, why not take everything you have mentioned and do a little experimenting until you find the lightest combination that does the trick. I'd also take a thermometer so you know what works for what temperature. That said, I also suspect that a single Z-rest is not going to provide enough insulation, especially since your clothing and sleeping bag will compress under you and thus provide minimal insulation. You might want to consider an inflatable pad, e.g. Cascade Designs Prolite-4(full length) or a Montbell equivalent combined with a foam pad like the Gossamer Gear Thinlite(1/8" or even 1/4"). I mention these two because they are the lightest options I am aware of, but there are plenty of others out there that would also work. My 2 cents' worth. Best of luck!

Tom,
My max/min digital thermometer only goes down to 14.

What do you use?

Where do you keep it?

Robert, As mentioned in the previous response I submit that your first issue is probably your ground insulation. This is the one area where trying to save weight can have serious consequences. I use a full length thermo-rest and a shorter lenght solid foam pad together when the weather will be below freezing.

Placing your jacket over you inside your sleeping bag can help keep it in place and not reduce its loft, but more importantly, by doing so you reduce the internal volume of your sleeping bag that you have to heat up. For me, the addition of a down vest would make your gear selection reasonable- if I had a good wool hat.

Have fun!

Jim……….

Richard,
I've got one that goes down to at least the mid teens(as far as I have pushed it) on my AltiTec altimeter and I suspect it goes down a fair bit lower than that; but without going downstairs and digging out the documentation, I can't be sure how far. I keep it on my ground cloth next to my bivy bag at night, as I'm primarily interested in the temperature at ground level where I sleep(or try to in marginal temperatures for my gear).

How snug is your bag? If a loose enough fit, you can wear longjohns and an insulating layer to great benefit. The bivy will add warmth as well. If it's snug, you can drape your coat over you inside the bivy.

A Z-rest isn't terribly warm, and I'd either add a second closed-cell foam pad or consider something warmer.

The good news is that you're unlikely to get temps as low as you're planning for in October, not that planning for them isn't a good idea. Improve the pad and I'll bet you're ready.

I tend to agree with most of what has been written above. I would also add that if this is going to be a more or less regular experience that you would like to have — camping in the really cold — then you should invest in the best ground insulation you can find or afford. I would submit that spending the money for good ground insulation will benefit you greatly in keeping you warm with your existing bag and down clothing. Weight be damned; I would invest in a Exped downmat 7 or Stephenson DAM. I prefer the Exped and would say that with this pad and a 1/8" gossamer gear Thinlight pad for an extra $9, you will be warm down to zero with no problem. From a packability standpoint, these two would be less bulky and more compressible than any of the combinations suggested above even though they would weigh more. I have been down to 19' with the Downmat 7 alone and slept like toast.

Richard,
I just Googled up the High Gear Altitec altimeter and the specs give the thermometer range as -4' F to 158' F with an accuracy of .1'. That's what they say, YMMV. For my purposes, accuracy within 1' would be just fine and I "think", a bit of subjectivity here, that it is at least that accurate.

Thank you for all the comments about the Z rest pad. I didn’t realize how important the pads were.

Maybe I should try my Thermarest Ultralite and a ½ inch blue foam pad from Wall Mart.

I have a Cocoon Balaclava that should keep my head warm

Mitchell said; “I have been down to 19' with the Downmat 7 alone and slept like toast.” Did you use a sleeping bag? Which one would you choose? Exped downmat 7 or Stephenson DAM.
Has anyone used hand warmers in their sleeping bag?

> My problem is my lack of experience with temps from 0 to 15 degrees at night.
It gets COLD. No, this is not a silly comment!

> Tent:Coleman exponent Inyo 2 (does this add 10 degrees?)
Nope. 3 – 4 F at the most.

> Bivy Cabela’s XPG ( does this add another 10 degrees?)
Nope. Opinions differ, but 4 – 5 F is probably the limit

> Pad Zrest
Thin!

> Is it feasible to use the above setup for a comfortable nights sleep?
Unlikely. You need more insulation, and some serious head warmth.

Tom,

Thank you. I use a zipper pull thermometer for sking and the air temperature at torso level is NOT the same as the snow temperature. And that zipper pull thermometer is hard for us old guys to read.

I am happy with my current 3 season thermometer, but am struggling with a winter set up. I just want to know if it is a green, blue special, blue, blue extra, or purple day.

Robert:
Of course I used a sleeping bag. Don't be silly:-D! I meant that I did not use any other ground insulation other than my DM7. I do not have any experience with the DAM, but others have posted about its similarity to the Exped line of inflatable pads. The key differences are that the DAM is made of what many have described as cheap pool float material but it is thicker than the DM7 and uses a higher grade down insulation. I would swear by my DM7, and many others who own this pad have also commented on the durability and warmth derived from using this pad. My bag of choice for weather down to the teens has been a Montbell super stretch #2 rated to 24'F. Using my DM7 and a 2' square of 1/8" evasote for my lower legs and then wearing my MB down inner jacket and pants inside the bag inside my tent, I have been warm through the night at 10,000' in the Sierras in mid October in the teens. I do sleep warmer than most of my hiking friends, but I would say that using a bag rated to 20'F combined with warm clothing worn inside the bag, and, as Roger said "seriously warm head gear" would allow you to get down into the teens at least.

Since you are only planning to be out for two nights, the issue of moisture condensate in your bag will probably not enter the equation. But if you do intend to camp like this more often or for longer periods, maybe it would be a good idea to consider investing either in a warmer bag, warmer ground insulation, warmer outer clothing or a combination of any of the above to make a more appropriate sleeping system. Just remember any of the improvements you make to a cold weather kit will also be usable in warmer situations.

I bring my WM Flight jacket and MB down pants along on trips where it "might" get as cold as 25' or 30'F in combination with my MB SS #5 which is only rated to 40'F. I use my DM7 as the pad of choice. In this way I am going to be comfortable whether it is 40 or 50'F or 25'to 30'F. You can carry a lighter more compressible bag if it is incorporated into a sleep system that provides flexiblity.

Brrrrrr!!!

I used my Marmot Hydrogen 30 degree bag with a bivy (adds ~5 deg) and a Big Agnes INSULATED Air Core Pad (good to 15 deg & oh so comfy) last week. I wore a puffball vest, long underwear, and a PSolar heat exchanger balaclava (it rocks!). It got down into the low 20's and I stayed comfortable, but I felt like I was nearing the limit. I could probably sleep down into the teens, but I don't think I would be safe in the single digits.

Wow Jason, I would have thought that your described sleep system would be good to at least 5-10 degrees. I guess that it is time to spend some serious money on a dedicated winter system.

Depends on how many calories you are burning…. but if you do go with a tent, candle lanterns put off about too much heat.

Guess I should have given a little more detail Robert. I based my estimate on the moderate wind and high humidity that I experienced on my most recent outing. In low wind and low humidity I could probably get ~10 degrees more out of it. Generally I don't plan for ideal conditions, so I would take my heavier winter gear for 5-10 degrees ambient air temp.

Somebody just posted that they felt cool in a similar setup at 38 degrees AAT, so YMMV.

Well, my best advice is – if your bag is large enough like my WM Megalite – is the following:
1. Wear expedition weight long johns & heavy wool "sleeping" sox W/ polypro liners.
2. Wear synthetic or down insulated jacket & pants. (These double as middle layers in the 20 F to 0 F weather when hiking of doing camp chores.)
3. Wear a warm balaclava & CLOSE THE BAG up to true mummy shape.

Works for me.

Eric