I am going into my first winter with a greyhound. Greyhounds don't have much body fat, and don't handle extreme temps very well. The advice I got was that if I'm hot or cold, the dog is hot or cold. So I've got some jammies for Trink, and she doesn't seem to mind them. And I've been burrowing under my throw, so I figure she should be wearing them. But how can I tell if she's too warm in them? Just watch for panting, etc.

Don't get something that will cover the whole body. Just something to cover the tummy will work. I.E. A shirt... I have a chihuahua and she has many clothes, just shirts. They keep her warm and she never seems to get too hot.

My dog... to the left wears clothes most of the time.. sweater's that cover his neck, stomach and back all the way to where his tail begins. I take his clothes off when he goes to bed at night or when I am going to be gone from home... I don't want them to turn into a choking hazard... you never know. I always have a blankie out for him... for him to burrow under in case he gets cold. I figure that as small as he is, he is more apt to get colder than I and at a more quick rate and plus their body temps are higher than ours.
For Trink They make these great beautiful wool capes... that fasten under their tummy's I don't have a clue where you would purschase one.
I would watch for panting or is she seeks out cool places to lie by the door, in the bathroom etc..

You can purchase them at Petco.

My baby has a small little furry cube with a blanket and stuffed animal in front of the heater... she goes there when she is cold... if we're going out so always has a shirt on!

In general, I don't think dogs need clothes. I do have a small sweater I wear when I have very young puppies out all day like maybe the day I ring bells for the Salvation Army. Xanthe will be almost 4 months old by then, and likely too big for the sweater. I do take a plastic tub with a blanket in it. I still end up with the puppy inside my coat sometimes.

I wouldn't wear clothes on a dog unless it was obviously cold without them. Except for the smaller dogs and younger puppies, usually a dog is fine outside as long as it is active.