Whether we watch groundhogs, or we just feel it in our bones, we all have our ways of deciding when Spring is here. (By the way, Punxsutawney Phil did not see his shadow this year.)
Since moving to this area, I have noticed that my allergies always pick up when a new season arrives. My nose is itchin', so I guess that means it agrees with old Phil the groundhog.
A year or two ago, someone told me to watch the native pecan trees to see when we were past all danger of winter freezes. Trees seem to take seriously the Entish motto "Don't be hasty," however. They still have yet to leaf out in my neck of the woods.
If you are looking for another indicator, maybe one from the slightly more hasty animal kingdom, there is a post over at the Lazy Gardener on the habits of alligators and what this means for gardeners. Basically, when the alligators get hungry, spring is here. Big Al, the 1,000 pound 'gator living in Gator Country near Beaumont is hungry, and he has a record for 100% accuracy.
As it seems unreasonable to argue with a hungry 1,000 pound animal with sharp teeth, I suppose I'd better start planting.