It gets just as cold here in the winter and mine still wants to go out just as much. She just doesn't stretch out in the yard like she does in the summer!
You'll need sweaters and coats. There are times I will have to put a sweater and a coat on mine. She refuses to wear boots though. I just have to be careful not to keep her out too long, because her ears and feet might get too cold. She actually prefers the temps in the 60's to the 80's and up.