Outdoor cat cold weather

Last summer a cat of uncertain gender began to live in our barn. I have been feeding and watering it. It is very shy and will not make physical contact but comes to the back door to eat. This week the weather is going to be very cold and I am concerned for it. The barn has a loft with lots of hay and the cat can also go under the back deck which I have built up snow all around so it's sort of like an igloo with one small hole to get in. I am able to lure this cat inside the porch and capture it but it is absolutely miserable inside and hides behind the fridge and cries. I am thinking of doing this anyway for the next week or so because its going to be near 0 a lot and I just feel so bad about it's being out in that. Should I just let it stay out in the barn or under the porch or should I get it inside again? Any suggestions would be helpful.

First of all, bless you for caring for this cat. It's great that you have been able to get him inside, but if he is truly miserable, the barn would be just fine. As long as he has a nice place with straw to snuggle in and protect him from the elements, he will be okay. Once he trusts you and realizes you aren't going to hurt him, he may want to come inside, it just takes alot of time. I have been caring for a feral/stray for over a year and just this week he decided he had enough with the outdoors-he has been inside since last Wednesday-he's smart-the weather is nasty here.

Once you gain his or her trust, it would be great if you could get him/her to the vet for a good check up and a spay/neuter. Keep working with him, it is so worth it.

Is there a way for you to get a small shelter under or around the porch? I make them with two Rubbermaid totes. I use styrofoam insulation between the two totes. I cut a 6" hole in both totes, lining them up to match. Link them with an 8" length of 6" round PVC. This makes an entry hole for the cats. Pile lots of straw on the bottom of the inside tote and he'll be nice and snug. pm me for details on the totes/insulation to buy.

They cost about $50 each and I've made almost 30 for our feral colonies here.

Even if you put a tote with an entry hole UNDER the porch and use straw inside, at least he's out of the weather.

I make my "shelters" for strays from "garbage"
I ask the vegetable's shop for some empty cages http://www.macplast.gr/mac/images/plas010.jpg and I look for insulation material from constructions left at the garbage tins... you can buy it, it is not expensive, I do not know the exact word in english, but is the same material used in the coffee cups (white plastic material made of compressed white balls)
I fill the cages inside with the insulation material and I wrap them with a thick plastic for protection from the rain, it is very warm and they like them a lot, one large cage can hold 1 large cat or 2 kittens

Shredded newspaper also is a good insulator for a little igloo vs a blanket which doesn't provide alot of warmth. Perhaps you could get a cardboard box, fill with straw/hay or shredded paper. I would not have box directly on the floor though-underneath would be too cold. Wrap the box though with blankets -tuna or moist cat food might tempt the cat.
Its going to be below zero here all week so I know what the cold is like.

Thanks for the advice. I guess at this point I am leaning toward getting it in.

Easiest if you can get him in. Don't worry about crying etc. Better he's warm than not! For under the porch sno igloo - get box like a paper
shipping box (they ship reams of paper in). wrap it in garbage bags and line it with the bags using duct tape to fix it to the outsideof the box (so its water proof on the bottom.). Stack about 2 inches of newspapers on the bottom of the box. cut a hole. If you can, get this box with the lid on top and the hole cut in one side and the newspapers on the bottom, into
the igloo area... Or build igloo round it...

If you've a barn and some spare bales of hay:

use bales of hay or straw to build a "bale house".
these keep ferals warm in VERY VERY extreme conditions. Bascially
stack bales of hay up to form a "fort" with walls on each side, consisting
of a bale of hay, a bottom that is couple of bales of hay lineup next to each other, and a top that is a couple of bales of hay. put lose hay/straw inside the bale house.

Leave a small open area for the cat to come and go. If you want, you can put a small sheep skin (wool retains heat when wet) inside... cats adore real sheep skin.... you can use some cat nip to temp him/her into the bale house...

Hope this helps!