Your body does have to burn more calories when it's cold to maintain its normal body temperature, assuming that you spend a non-trivial amount of time outdoors rather than in climate-controlled buildings where it's pretty much the same temperature year round. However, it's not a big difference, and is probably negligible when it comes to weight maintenance. Also, some argue that we're subconsciously wired to want to eat more during the winter to build and maintain a layer of fat to protect against the cold, though I'm not sure whether that's really the case.
When people tend to gain weight in the winter, it's typically because they're spending less time participating in sports, or walking, or other types of outdoor exercise that many people reserve for warmer seasons. But if you make a point to keep your overall activity level about the same, and you don't fall into the trap of increasing your calorie intake, you shouldn't have a problem maintaining your weight through the winter.
