Does Winter...and the lack of sun drag you down?

New experiment here.  Sometime around late November as it's dark early and colder, I casually notice a drop in energy levels and output.  This is not a "Winter Blues" depression rather a noticeable drop in the "buzz" that I experience daily from my work, family, etc. 

By January, I've usually bottomed out and continue on until those magic Spring days where we bust outside and frolic well into the night.  This happened to me in California as well though not as it's not just a Midwest thing.

I'm chalking it up to lack of sunshine/UV rays.  So, in a bold experiment :) I'm going to hit the tanning booth with some regularity for the next month or two and will report back.  Please no warnings on the damage of UV rays.  I'm aware.  I'm also fully prepared to accept the ridicule of my readership (Tom B.) but I'm viewing this as a medical experiment. 

I'm guessing there are more than a few of you that experience this effect.  More to come.