The leading Groundhog Day data source

About Groundhog Day

Groundhog Day is a lighthearted holiday celebrated annually across North America in which ‘prognosticating’ animals predict the onset of spring.

Traditionally, on February 2nd, various groundhogs across North America are consulted by local public figures (often a mayor) for an annual weather prediction:

  • If the groundhog ‘sees its shadow’, it means 6 more weeks of winter
  • If the groundhog doesn’t see its shadow, spring will come early

Since groundhogs can’t speak English, they communicate their ‘prognostication’ in ‘Groundhogese’ — a language known only to specially-ordained groundhogs and the presiding officiant.

Punxatawney Phil is the most famous prognosticating groundhog, largely due to starring the 1993 Hollywood film “Groundhog Day,” with Bill Murray in a supporting role. However, there are many Groundhog Day ceremonies across North America, not always strictly including a live groundhog, but all of which follow the central premise of an animal predicting the upcoming weather.

So that’s Groundhog Day in a nutshell. However, if you’re a curious person or you’re not yet 100% clear on the scientific method used by groundhog forecasters, I would direct you to a more comprehensive history of Groundhog Day. It’s just as weird as you think.

About is the leading data source for North America’s prognosticating groundhogs and their yearly predictions. provides past predictions for individual groundhogs, as well as aggregate yearly data comparing the number of ‘early spring’s to ‘longer winter’s.

Our mission is to provide Groundhog Day data that is free, accurate, and portable. Every year, there are a spate of newspaper articles doing some kind of data analysis on Groundhog Day results — makes that easier than ever. Historical Groundhog Day data is collected from a variety of sources, including an academic paper: Broadscale Assessment of Groundhog (Marmota monax) Predictions.

We are always open to improvements or suggestions, and always keen to add new groundhogs. Please get in touch if you have any questions and/or feedback.