Grubhog Day is a holiday celebrated in Amphibia. It's very similar to Groundhog Day in that a creature pops out and tells the weather but, in Amphibia, they cut the grub open and look at spots on the liver. If there's spots on the grub's liver, it means two more weeks of winter. According to Polly, this is the only day that all the inhabitants of Wartwood take a break from their jobs and attend the fair.
Grubhog Day consists of a very large fair, with various rides and attractions and food and shop stalls offering various tasty treats and items. Their is also a night ceremony at the end of the day in which the Grubhog is washed and fed, before being cut open to determine the future weather.