Groundhogday

I have never really understood groundhog day. Not the part about using a small animal to determine if we are in spring or winter, that part I am just fine with.

It's the shadow thing that, year after year, drives me crazy.

Think about it this way, when it's dark and cloudy out there is (obviously) a smaller amount of light. Less light means that shadows are much fainter. On the opposite side, when it is bright and sunny out there is a bigger contrast in light vs. dark, meaning that shadows would be much easier to see.

And what season is known for being dark and cloudy? Winter.
What season is known for being relatively sunny? Spring.

Yet for some reason, on groundhog day, if the groundhog does not see his shadow (like he didn't yesterday) that means that we are headed straight into spring - not winter. How does this make any sense?

Every single year this confuses me, and the ironic part is that it has nothing to do with the groundhog.