Using a thick piece of cardboard, cut out a large circular piece according to your final size needs. Cut out a second slightly larger circle and place the smaller over the larger for a two-layered brim.
Paint the cardboard in the color of your choice. A traditional top hat is black, which contrasts well on a white snowman.
Take an empty cereal box and cut out two large rectangular faces. Fold these into two halves of a cylinder. Join this with a generous amount of tape.
Color the top cylinder. Attach it to the brim with staples or glue, depending on your needs and time.
For a top hat to stay firm, difficulties can occur as the tall cylinder can fall. One option is to find a sturdy stick and fix it to the top of the snowman's head like an antenna before placing the hat on it. This can help a tall top hat stay on your snowman's head.