Like any mountain environment, the weather in Bansko can vary greatly (and rapidly). Bansko SKI ZONE averages 459 inches of snow each winter, but that’s a measurement taken on the mountain. The valley receives less snow but know this: there will be snow on the ground all winter long, so plan accordingly. The roads are rather flat and generally well-plowed, so if you're thinking about renting a car, rest assured that driving in the winter is relatively easy. It's not uncommon for us to get inversions, where the temperature on the mountain is actually warmer than at the base or in the valley. In any case, plan to be in immersed in a wintry wonderland where the weather can change at the drop of a hat, but no more so than any other high alpine location.
Weather Links - NOAA Forecast for Teton Village - Snow Report - Average Temps and Precipitation