Gray Eyes, Gray Skies

I don’t know why it is that as soon as the weather turns gray (like it is right now), I suddenly feel the urge to write.  It’s possible that I feel so energized and content when I’m outside in the sunlight that I don’t need the emotive outlet of my writing as much.  Or that summer makes me lazy.  Or I need to write more when I’m tired and cranky.  I’m sure we all go through less verbal times on our blogs, but do any of you know why?  Is it worth knowing?