Rubber Ducky Day is celebrated on January 13.
Though rubber ducks have existed since the rise of the rubber industry in the late 19th century, Ernie’s “Rubber Duckie” on Sesame Street has played a large role in boosting the popularity of the rubber duck since the 1970s.
Muppet Wikia has more information about Ernie’s Rubber Duckie specifically, including how the show replaces them, since the original they used is more than 40 years old. The “Rubber Duckie” song was nominated for the Best Recording for Children Grammy in 1971.
“Rubber Duckie,” sung by Ernie, Sesame Street (1970)