It is not possible for your eyes to appear lighter in winter. The color of the eyes is determined with the genetic genes which will not easily change unless you have the problems in the body. When you change the color of the eyes, you'd better go to see the doctor and check the eyes. You could use the eye drops to bright the eyes and moisture the eyes.
I don't think so, The color of the eyes usually inherit from parents. And the color of your eyes is born to be and won't be change. But when we getting old, Our eyes my less bright than we young. Nevertheless, The color of my eyes won't change. But when people meet something or somebody they like, their eyes may brighter than the time when they feel upset. But as far as i know, the season won't change it.
Well, no, your eye color will not be lighter in winter, for eye color can not change with seasons. Generally speaking, the eye color is hereditary and they are born with you. And they can be the same in most cases. But on the other hand, it can change with the emotion and weather. For example, if your emotion is low, the eye color can turn to light grey and light blue. Also, the weather has some influence on eye color too. In common, when it is really sunny outside, it can cause your eye color to become brighter. By the way, some drug which will have side effect that it can change the color of your eyes. but there are nothing to do with the season, such as winter or summer.