Older origins...

Groundhog Day: lots of snow and very cold; I'm sure all over the Midwest a groundhog has emerged and seen his shadow: according to legend that means six more weeks of winter. If they hadn't seen their shadows, an early spring could be expected. The day coincides with Candlemas and has the same meaning traditionally, "our ancestors predicted the weather according to the conditions on Candlemas day [Link]:

If Candlemas day be fair and bright, Winter will have another flight; But if it be dark with clouds and rain, Winter is gone and will not come again.

So, if the sun is out the hairy guy will see his shadow but if it's cloudy he won't. And as that last link suggest both have roots in the pagan festival Imbolc which celebrated the beginning of Spring after the usually cold, dark Winter.