Congratulations and thank you for adopting a dog!
Kindly tell us if you plan to keep your dog inside your home, or outside. Assuming inside, I think your dog will tell you, and no need to worry, especially if anything close to a Collie! Just put special notice to the paws! - if your dogs, unlike mine, are OK with "shoes" please put them on during walks when it is really cold.
P.S. I am now in Japan, with two circa 15-year-old mixed-breed abandoned dogs adopted in Shanghai. When living in Finland in between, one of them (probably mixture between Shih Tzu and Maltese) had trouble as his personality did not allow the shoes which was funny, so during the winter walks I often had to stop, take away my gloves, and carry him while warming up his paws with my hands.