What is GroundHog Day?

On February second 1887 Groundhog Day was celebrated at Gobbler's Knob in Punxsutawney, Pennsylvania (USA), starring for the first time a rodent meteorologist.

According to tradition, if Phil, Bill or Chuck the groundhog comes out of its hole on this day and sees its shadow, there will be six more weeks of Winter weather; no shadow means an early Spring.

Here´s a tongue twister inspired by its Algonquian name (a Native American languagewuchak. 
How much wood would a woodchuck chuck
if a woodchuck could chuck wood?
A woodchuck would chuck all the wood he could
if a woodchuck could chuck wood