Get a Good Pair of Mittens
Just to clear something up, it’s going to be as cold as a snowball’s $&*@ during this apocalypse. In many scenarios the sun will be blotted out by dust or pollution and only those that are able to withstand the long extreme cold will survive. Don’t think that you can just head to Miami either, everyone is going to be heading there, and not just Cubans and Grandmas anymore. You’re going to need to avoid people for a while so be prepared to endure some tougher climates. Getting a good pair of mittens should be number one.
Feel free to pack a pair of gloves if you like. I wear thick wool gloves most days because I need to use my hands often. Gloves are worthless though below 10 degrees and it’s certainly going to be much colder than that. Mittens are always going to keep your hands warmer and I’d sacrifice a bit a dexterity to keep my fingers from turning black and falling off.
I highly recommend these Army issue mittens for extreme cold. Aside from being the warmest mittens I’ve ever owned, they are tough and you shouldn’t need to own more than one pair. Also there is a sinchable canvas sleeve that protects you from snow and the “bear” hide covering is a great Kleenex.
You can find these on Ebay or in any Army surplus store. I got mine for 10 bucks.