I have Wiggy's Ultima Thule bag, rated for -20 oF
http://wiggys.com/moreinfo.cfm?Product_ID=59&CFID=9730099&CFTOKEN=86247224

It's fairly heavy, bulky, I hate the mummy style... and I get cold even in late summer/early fall (camping up high in the mountains)

I've upgraded my sleeping pad to one of those with down in it. Now I need a different bag. Hopefully lighter than the Ultima Thule, something of intermediate width in the foot section (not a full mummy, and not fully rectangular), and compressable... and warm.

I often wonder if something modular would be better, a lighter bag to start the night with, when it is still warm, and an insert or pull-over later in the night...
(I know, I'm a very finicky sleeper...)

That sounds an very unforgettable experience ,thanks for sharing.

Frans, where does the cold start when you first notice getting cold? Do you get cold on your lower side, especially on a shoulder or hip gradually when you are on your side? If so, there is not enough insulation in the pad under you. Initial cold spots can be head, neck, one shoulder, both shoulders, hip, knees, feet... I'm not being goofy. Each of these tells you something about what you need to change in the way of bag, pad, etc.

In really cold weather I take two sleeping bags if I'm camping near a vehicle or with horses, (though not when back packing). One usually goes over the top unzipped like a quilt, though sometimes have put one inside the other. With one bag inside another, you can get inside the outer bag and under the inside bag rather than in it. That positions the entire inner bag over you, and puts three layers of sleeping bag insulation over you, and only one under you. That works well with a roomy outer bag and really good insulation layer under you for a pad.

Hmmm... hips region I would say.

I remember one October trip, when I got caught in some nasty weather, about ten miles in. I used water bottles, and heat packs to make it through the night, which from weather reports likely went down to about -30F. I guess most folks would be experiencng some cold in those conditions.

But I also remember an August long weekend trip, where I got cold during the night, with temperatueres way above freezing.

Maybe I'm just a wimp :-)

Try using a good quality down bag. I expect that the better drape will resolve many of your issues. A down bag will be a great deal lighter and much more compressible as well. This becomes more true for cold weather bags.
For cold weather consider adding a closed cell sleeping pad below your down filled mat.
I'm not a fan of trying to make one bag "do it all" from summer to winter. If severe cold is possible then carry the big bag, otherwise take a good three season bag.
Overbags do work but every two bag system I've tried or seen weighs a lot more and is much more bulky than a good single bag that is suitable for the same temperature range.

I think you could make the case a 2 bag system would be superior in that environment. Use down for draping , weight , compression ,with a light synthetic to add warmth and move moisture out of the down.

I know that is the route I'm going for temps below 0 , but I'm going to make a lightly insulated bivy to do the job, really pretty much an over bag but more like a bivy

The solution to your problem is simple, chuck the "Wigsack" and call Evan Jones at Integral Designs in Calgary. Buy an ID XPD-1 "Rockies" down bag from him, in the size suited to your physique and use a Z-Rest from MEC under your downmat.

ID down bags are at the pinnacle of quality in sleeping sacks and while costly, it will, with reasonable care, last your lifetime. I have owned/used most of the highend down bags available in North America, since my first in 1968 and ID and Valandre are "the best" overall, IMHO.

Evan makes a "broad" size range that is just perfect for we who do not like the "cokebottle" or "coffin" styles of mummy bags and mine is a custom XPD-II that he built for me in 2003. It was NOT "cheap" and has an "Endurance" shell,the ONLY wpb shell material to buy, IMO, but, it is beautifully made and would work to -40, no problem. I have slept out at this temp., this is not mere speculation.

I also have an ID "combo" rig,made of the "North Twin" and the "Andromeda Overbag", this is my favourite hunting setup and it is versatile, warm, dry and compared with the "Wigsack" I had. Check out ID's site, they make fine gear.

Big bags or non fitting bags require more body heat to warm space. Simple--get a bag for your body structure.

Does ID hide the sleeping bags somewhere on its web site? I can't seem to find any mention of them.

Sometimes a bag can be too warm. If you start the night warm/hot, you can start sweating, then in the middle of the night you get chilled. Try venting the bag so you are just barely warm. This works for me.

For what its worth this is what I do after 30plus years of back pack hunting. First off I live in Oregon and back pack hunt Spring Bear in the early spring to late archery elk in late September. My system is light and compact. First off make sure whatever pad you are using has an appropriate R-value. I use the new Neo air which has an r-value of 3.2 for summer and archery elk hunts and spring bear I use the four season neo-air which has an R-value of 5.2. Second buy a high quality down bag. I use a Montbell UL-3, its a down bag with a 30 degree rating, then I keep at the feet of the bag a Sea to Summit Reactor Plus sleeping bag liner which uses thermacell extreme insulation and weight is around 6 ounces. This combo keeps me warn into the high teens. My total sleep system weighs 4.2 pounds, thats bivy sack, sleeping bag, neo air mattress, and sleeing bag liner. Very lightweight and efficent

For what it is worth, I did not mean to dish the Ultima Thule sleeping bag. I meant to stress that it is me that is always cold, and hoped for some suggestions. I know people that use the Wiggy's bags and are very happy with them. I have used mine for about eight years now, and it still looks like new, almost anyway.

I also meant to stress that I don't like the mummy model, which is not brand-related. I never realized how much I move my legs when sleeping until I couldn't.

I hoped to get some suggestions on the bag that doesn't exist: minimum bulk, minimum weight, roomy enough to not feel constrained from the hips down, and always warm... might as well add cheap too!

Thanks for all the suggestions.

Frans, I've got 20 degree and a 0 degree Wiggy's bags..........both XL long. I love how they fit me, and feel they meet their temperature ratings when light clothing worn. At least for ME. They're bulky and heavy, but great other than that.

Just my experience, and it sounds like things get a lot colder up there where you hike. Do you wear clothes to bed?

I would look into Montbell sleeping bags if you want something light, warm and roomy.

To small of a bag makes you cold as well since you compress it to much, especially in the legs.

I know you already know this but going to bed clean , dry and warm can do wonders, and I think a pad like the downmat gives you comfort plus warmth. If you choose synthetic it will be bulky. Down can reduce the bulk and weight, but given your environment some sort of synthetic outer layer would be a good idea to keep moisture out of the down , perhaps even a vbl.

A lot of times simple garbage bag vapor barriers can be used on cold areas such as your feet and make you feel warmer.

Some of it depends on where you feel cold from, what are the first areas, back , feet, etc.

Also, what are the coldest temps you routinely see?

Hey Frans - I think these guys are in some way connected to Integral Designs and are in Calgary. Can't recall but I think mine is an ID Renaissance.

http://www.integraltactical.com/

That site IS "Integral Designs"and, last time I visited, it listed the various down bags Evan manufactures. The "ID" brand was sold to "Rab" some time ago and I do not like the products sold by them as they are Chinamen gear.

But, the ORIGINAL ID bags, made in Calgary are simply superb and trying to "cheap out" here is false economy. You do NOT need all of these fancy new camo stretchy "hunting" clothing, systems for this and systems for that, it has become farcical. BUT, YOU DO need a good sleep every night if you are going to really hunt and thus a top end bag is money well spent.

That's the bag I am looking for also!

Good suggestions in this thread.

FWIW I often add a second closed cell pad under me in cold conditions, purely for insulation, not cushioning.

The first place that gets cold with a mummy or most any cover is either a thin spot or gap in insulation or where your body sticks out and compresses the loft a bit, such as hips or sholders. I have very wide shoulders and rarely zip up a mummy because of that.

You might try adding a heater inside the bag: tear open chemical hand warmers add a lot of warmth and are handy. They make larger ones that cover a large section of back or belly. I use them a lot, ideally inside a loose fleece or outer layer, with one thin layer of something next to skin to keep the hand warmer from touching skin directly. One in a sock at the ankle, one in a chest pocket, etc. Even if they shift around they usually keep producing extra heat inside the sleeping bag.

I sleep in cold with a fleece toque and neck gaiter that has a long and wide flap front and back down chest. Something on the head is a must for me, if nothing else a flap of fleece from a jacket used as a pillow.

Most likely you have thyroid issues, get it checked.

Good comment! I have thyroid disease and during the early stages before we got it leveled out I would get cold quickly and deeply at times when others around me felt normal or merely cool.

There are about 50 symptoms or more of off kilter thyroid and some could be caused by something else. Among them: loss of low light vision or night vision so you need a flashlight when others can see to walk easily, accelerated hair loss, abnormal sweating (too much or too little), eye pain in bright light, slight whispery sound to voice, sensitive skin, change in skin tone to dry or oily, ridges on toenails, fatigue, muddled thinking or unable to remember a phone number long enough to dial it, fast or abnormal heart rate at times... I had absolute cravings for certain foods at times as well.

I think it is easy to check with a blood test. The unusual susceptability to cold is enough by itself to have it checked.