St. Lucia Day is celebrated in Sweden on December 13 th , the longest night of the year. Celebrants wear a wreath with a single candle. The holiday falls in late October. Celebrants place small oil-filled lamps along the parapets of temples and houses, and also float them on rivers and streams. They documented treatment of SAD using lights.
Doctors prescribe exposure to a light box in the morning.
Generally the light boxes use a bright light with a frequency spectrum closely simulating the frequencies of natural sunlight. The required length of exposure depends on the severity of the winter depression. While no one is certain why this helps, scientists hypothesize that it has to do with shifting the body's internal clock. And there are many testimonials to the success of light therapy. Maybe we can learn something from plants, who also need light.