"The groundhog is the largest sciurid in its geographical range, typically measuring 40 to 65 cm (16 to 26 in) long (including a 15 cm (6 in) tail) and weighing 2 to 4 kg (4 to 9 lb). In areas with fewer natural predators and large amounts of alfalfa, groundhogs can grow to 80 cm (30 in) and 14 kg (31 lb)."
http://en.wikipedia.org/wiki/Groundhog
"Groundhog Day is a holiday celebrated on February 2 in the United States and Canada. According to folklore, if it is cloudy when a groundhog emerges from its burrow on this day, it will leave the burrow, signifying that winter will soon end. If it is sunny, the groundhog will supposedly see its shadow and retreat back into its burrow, and winter will continue for six more weeks.[1]"
"the National Climatic Data Center reportedly has stated that the overall prediction accuracy rate is around 39%.[25]"
http://en.wikipedia.org/wiki/Groundhog_day
I created this maxicard although I knew that the postmark will not be very visible. I wanted to leave the text unobscured, and I hoped that the ink of the postmark will be good enough. Hoping is free - anybody can do it. Anyway, you can see the postmark on the backside, below.
The FDOI (First Day of Issue) postmark was applied by USPS (United States Postal Service) in Toronto, Canada.
Is Canada [officially] part of USA? :)
No, but it was during CAPEX (Canada Philatelic Exposition/Exhibition) and USPS decided to have there the FDOI postmarking event for that great, beautiful 50 stamp-series.