The groundhogs — along with a tortoise, whose emergence from his winter hibernation foretells the coming of spring, and a prairie dog statue, whose shadow at sunrise predicts how long it will be until spring arrives — were ranked based on their accuracy over the past 20 years, using the March temperature averages for the U.S., NOAA said.

Punxsutawney Phil usually makes his weather call early in the morning. It typically happens after 7 a.m. Tradition says Phil seeing his shadow is a sign that the next six weeks will bring wintry weather. If Phil doesn't see his shadow, it means an early spring.