Weather can be sunny, stormy, dreary or unpredictable but then so, too, can your mood. The way you feel on any given day may actually be intricately tied to the weather forecast in ways science is only beginning to understand. Many people are now aware that spending time outdoors on a sunny day, and allowing the sun to shine on your bare skin, is necessary for your body to produce vitamin D, which also plays a role in serotonin production. Serotonin, the brain hormone associated with mood elevation, rises with exposure to bright light and falls with decreased sun exposure. This is one reason why bright-light therapy is so effective for treating people with seasonal affective disorder (SAD), which is sometimes referred to as 'winter depression.' This is only the tip of the iceberg, however. A sunny day can make you feel inexplicably happy, but only if you can frolic outdoors. People who are stuck indoors on a sunny day may feel their mood plummet, and the weather also has significant