Midpoint between solstice and equinox.
Found this article on Animals and weather at Cosmic log
http://cosmiclog.msnbc.msn.com/archive/2008/02/01/627079.aspx
Ken
Always wondered on the significance of grounhog day. Odd that the pics on that site are the same as ones shown on BBC news at 06:00 today.
Used to think everyone had minced pork for lunch. 
and…there were us ancients Brits thinking it was not until the 4th February… 8OImbolc…I had better look at the stone pillars again!!! 
Looks like the Canadian groundhogs are predicting an early spring:
the weasel we have … six more weeks of winter. Well… let see …
we are to have snow, freezing rain and then rain , Sunday through Monday. Hope it freezes its tail…