I use it on those super cold sub 40 deg days for
355711
This will keep your head warm in the coldest weather. I use it on those super cold  sub 40 deg days for kitesurfing
4018532
Very effective in cold weather, down into the 30'sF it kept me warm. I bike commute in mine, and occasionally on long inclines or otherwise laborious periods I have to pull it down to breath more easily, but it's definitely wearable even if you need to pull the front down beneath your chin.
3287158
i have a balaclava, but it wasn't standing up to the performance in the cold weather.  My face was freezing in the cold wind chill going down the ski slope.  So I bought this based on the review recommendation.  This is versatile, i can pull the face thing down if i get a little too warm or i can pull it up to cover mouth area just below my nose or i can pull all the way up to leave very little expose skin on my face in a really cold wind chill.  This keep my face from freezing.  The only down side is this thing is a little smelly right out of the bag, so i hand washed it with soap and it did get rid of the smell.  I see a lot of people have this on the slope.  This is one of the must have for cold winter gear.
4520035
Works great in warm weather, if you you need to use it at 20F and belo - you might have a problem
3987006
I use this daily! Usually keeps ice in my water for about 4 hours.
233677
Pleased to say that its still working through a dozen days of 15 below zero temps.
1832939
i like this product because it met my needs.  i don't think i would recommend it for extremely cold weather but it's good when you want some extra heat on your dome or want to use it as a base layer under a helmet or bigger winter hat.
342199
I'm a landscaper and I fill this with ice and water every day.  It keeps my water cold for about 12 hours which is more than I could reasonable expect.
1205405
I got this not really expecting it to perform well, but I needed a lightweight and compact sleeping bag for a camping tip that I knew would get down to the 40's at night. That said, its perfect. Stuffs small, stays warm, didn't tear or anything horrendous. However, I would not use this bag in any temperatures lower than 40. I had a base layer on and at around 42 I definitely started to feel the cold. Not enough to prevent sleep, but I could tell that if it had gotten any colder I would have lost sleep.
1559870
Bought the black arctic parka to help me survive months November-April over here in Western Alaska. Temps this winter, on one horrible occasion, dropped to -44F ambient (-60F windchill) and this coat, along with five or six of my favorite wool sweaters, kept me warm enough to stand outside for a couple hours at a time to check in dog mushers - and I didn't have to be medivaced for frostbite. Still, it wasn't particularly comfortable- I'd say the range for this coat for me is maybe 25F down to -20F. I'd also like to note that after just one winter of use, you can definitely start seeing wear and tear, particularly around the pockets and seams. One of the elders in the village has the same coat, and I can see the same discoloration in the navy model. Overall, it works for bush Alaska travel, but would expect it to hold up better at its price point.
2311520
I have a temperature regulating comforter which I have really loved.  I don't at all understand how these things work, but instead of sleeping under a pile of quilts, I am able to just use this one comforter.  We have a very cold house (the furnace went out and we really can't afford to replace it).  I use the same comforter all summer (we have never had central air).  At both extremes, I stay pretty comfortable with the comforter.

So I hoped the pillow would expand on that a bit.

So far, so good.  It is the dead of winter, so I haven't been able to test it out when it is uncomfortably hot.  But for the cold temperatures, I find that I am not always diving under the blankets when I get to bed -- or at least I don't stay there as long.  The pillow doesn't necessarily help my nose stay warm, but I do seem more balanced in my head and neck.

The king size is pretty obnoxious to stuff into a pillowcase, but it does fit well once inside.

I'm happy with this
2987498
I tend to get cold even in the tropics when diving.  Adding this to a shorty-rental has worked great.  I have also used it in association with a thin neoprene top for body surfing, and toss it in my gear bag when kayaking.  Works great and fit well.
785144
I've used this de-icer for almost three months during some bitterly cold Maine days, and the unit has managed to keep
most of the water in my bird bath ice free.  I've noticed some ice on the edges at times, but this winter has been
unusually cold.  (sub-zero on some days)
2798460
Works great, I do live in a cold climate so I remove it after each use, but that is very easy.
It is better than expected
4890080
Use it for jogging in cold weather - performs great
2222165
So it stays at about 50 degrees and if you remove the white cover over the inside fan it stays at 40 degrees I found putting a few sheets of insulation under it cause the transmission on my big rig  gets real hot  once the insulation was used it runs good but after 2 weeks of  solid usage the Finns frost over all and all not a bad cooler
1014313
Bought this for cold mornings (below 50 degrees) riding my motorcycle.  Although it doesn't block wind quite as effectively as I expected it to, it still made a big difference on those cold mornings and helped my face and ears stay a little warmer.  For the price, it's hard to complain.