While often considered a spring and summer pest, carpenter ants can start showing up http://onlinelibrary.wiley.com/journal/10.1002/%28ISSN%291526-4998 as early as mid to late January in some parts of the country. With just a couple of consecutive sunny days temperatures can warm up enough to create some activity.
Such an early appearance of carpenter ants is usually sporadic. You will not necessarily see constant activity but rather see a few on one day and a few on another. However, just because they appear to go away for a while doesn't mean that they are gone but rather that they are just not currentl