Condensation takes place when warm air comes in contact with colder and dry air. During the winter months, the outside temperature is less as compared to our homes. This is due to the insulation we use and the heating we are using at home. Kitchens are even warmer, especially when we are cooking. This causes the inside air to become warm and rise up. When this air mass comes in contact with the windows (which are colder), the warm air loses its temperature and its capacity to carry water. This causes droplets to form on the inside window surface.
We can observe similar condensation on our bathroom mirrors, when we are using hot water for bath. The remedy for this is either opening the window or using an exhaust fan in the kitchen or bathroom.
Hope this helps.