Dennis Eddlemon, 50, of St. Louis County, dressed up as silent-movie star Charlie Chaplin in a dark suit and derby hat for the event Saturday, the St. Louis Post-Dispatch reported.
"It's so nice out here. What a beautiful day," said Eddlemon.
There were 449 participants in the polar plunge, the Post-Dispatch reported.
Plunge organizers last week broke ice near the shore and used a bubbling machine to make the water move continuously. Swimming geese in the area helped, the newspaper said.
But the morning of the plunge, organizers shot off fireworks to scare off the geese, said Matt Lauer, St. Louis metropolitan area director of Special Olympics Missouri.
Officials said the plunge raised $89,800 by Saturday.