Seasonal Affective Disorder
If your mood gets worse as the weather gets chillier and the days get shorter, you may have "winter depression." You may have what's called seasonal affective disorder, or SAD. The condition is marked by the onset of depression during the late fall and early winter months, when less natural sunlight is available. It's thought to occur when daily body rhythms become out-of-sync because of the reduced sunlight.
For more information about SAD, please click here.