So, the weather in Portland has been pretty snowy which is a touch unusual! As most folks have been inside and not out attempting to drive on icy and snowy roads which are not plowed I decided I’d take my HT for a walk in the cold weather and test methods of keeping it warm enough to not have the battery fail as the temperature is dropping to ~18F with wind chill. My partner and I have been walking to the grocery store and taking our dog out so I decided to test an external antenna I’d built to mount on my backpack a year ago in the gnarly weather. I did some tests with APRS and some 5w FM phone as well. The theory here is that keeping the HT inside the fairly sealed bag would preserve some amount of air that’s warmer than the bag’s surroundings. It seemed to work as I was out with this setup for a few hours at a time and battery performance was within expectations.
In order to not go stir crazy I’ve been taking walks with my partner and we’re close enough to a grocery store to just walk and pack our food in our bags which is very fortunate. I’ve taken the opportunity to test different ways of carrying the HT so it doesn’t get too cold, and to test a MOLLE antenna holder with a simple antenna and counterpoise setup. During the grocery store run pictured below I was able to reach stations in SE and NE Portland with a strong signal. I was between 2 and 9 S units into a station in Battelground, WA as well depending on structures around me. The antenna I’m using in this picture is a Nagoya NA-771. I used that instead of my Signal Stick because the signal stick doesn’t stay rigid in cold temperatures and will curve and lay over giving poorer performance. The speaker mic was used as both a speaker that I could hear outside the bag and as a sacrificial component in the event something gets too wet. A $30 speaker mic is much cheaper than a new HT. I did test the SWR on this setup and 2m performed very well near 1.2, but 70cm performance was poor with the SWR being near 2.8.
Small bit of paracord holds the mic in place, long bit holds the HT up in the bag. 
Speaker mic clipped to backpack strap.
The small bit of orange paracord is used to secure the speaker mic for cable routing purposes. When the mic comes un-clipped intentionally or on accident this cord makes it easier to grab and replace or remove and use. The longer orange paracord holds the weight of the HT in side the bag so the antenna cable and speaker mic don’t hold it up. It’s also necessary to hold it up in the bag to make sure there’s enough speaker mic cable to reach outside the bag and to my shoulder.
The HT holder inside the bag is suspended by the longer bit of paracord that runs through a loop on the HT holder. This suspension system also makes it easy to load the bottom of the bag with heavier items that might otherwise crush the HT or damage connectors.
Individual components 
Being assembled 
Antenna cables wound up 
Entire assembly set up for mounting.
The above gallery shows the antenna assembly set up but not mounted to the webbing on the backpack.