Jim Todd
RCA President
OMSI Director of Space Science Education

Groundhog Day 2024 on Friday, February 2 is a popular holiday with a long history and an astronomical event. It is near the halfway point between the winter solstice and the spring equinox, and its midpoint is a seasonal marker reminding us that spring will return once more. Groundhog Day derives from the Pennsylvania Dutch superstition that if a groundhog emerges from its burrow on this day and sees its shadow due to clear weather, it will retreat to its den, and winter will go on for six more weeks; if it does not see its shadow because of cloudiness, spring will arrive early. Many weather researchers questioned the groundhog's accuracy in predicting the weather, but some of the groundhog's fans may not agree!

In astronomical terms, Groundhog Day is one of eight major seasonal subdivisions of every year. They include the March and September equinoxes, the June and December solstices, and the intervening four cross-quarter days. The four cross-quarter days are Groundhog Day (February 2), May Day (May 1), Lammas (August 1), and Halloween (October 31).

The cross-quarter day (the midpoint between an equinox and a solstice) got its start with the Celts who called it Imbolc or lambs' milk as lambing season had just begun by February 2. The Celts also called the holiday Brigantia after the Celtic female deity of light, reminding them that the Sun was halfway on its journey to the spring equinox. Later, the Christian church called the holiday Candlemas, referring to the candles lit in churches that day to honor the presence of the Christ Child in the temple of Jerusalem. German immigrants to Pennsylvania brought their Candlemas legend with them in the 1880s. Since badgers weren't to be found they adopted the groundhog instead.

Old Groundhog stretched in his leafy bed.
He turned over slowly and then he said,
"I wonder if spring is on the way,
I'll go and check the weather today..."
~Author unknown, "Groundhog Day"