Carpenter ants are not a welcome sight in your house, especially in the winter. Cold wet weather in the winter is the ideal time for carpenter ants to get the upper hand in your house; using the studs, plywood, o.s.b. and insulation to tunnel and make their satellite nests. So why in the winter, well- because you heat your house. Outside, carpenter ants go into a pseudo dormant state in cold weather but in your house they can continue to build since they have stored food in their satellite nests. The good news is that, carpenter ant treatment can be done anytime of the year, as they can continue to do tremendous structural damage long before the spring arrives.
https://gogreenpestcontrol.ca/carpenter-ants-again-in-the-winter/
https://www.linkedin.com/pulse/carpenter-ants-again-winter-randy-bilesky/?published=t