Ants live under rocks. Your driveway and patio are like big rocks to them. Once they colonize these areas, it is a simple expansion into your basement. They can be in the walls, under the floor, behind insulation, and in wood components.
It can be helpful to treat these areas. This is true, especially during the colder months. During this time these basement nests are the only active part of a much larger colony. Baiting ants in the less occupied basement is better than in the living space. Bait draws them out. And it can take several days for the activity to stop. Liquid bait stations or granular bait on the ledge atop basement walls work well. The middle support beams provide a pathway into other parts of the house. Baiting on this can stop them from popping out of an inner door frame or baseboard. Remember the goal is to track ants back as far as possible and apply products to these locations. During the colder months this is usually the basement. During the summer, this is outside.
Yes, bait is better applied outside during summer. It is best to draw them out, instead of in. During winter, they are only in, so anything goes. In our experience, baiting is better than spraying basements in most instances. We find that placing different baits provides the best results. Use patience in winter. The warmth of the structure can trick ants out of dormancy. As the temperature continues to rise, more ants become active.