As recently as the 1970s, the hat-wearing public abided by start and stop dates that fell on or near September 15 and May 15, which were known as Felt Hat Day and Straw Hat Day, respectively.

POLICE are searching for a man last seen wearing a grey felt hat, after he allegedly stole a $30,000 diamond from a Brisbane City jewellery store.

Carter dyes the fiber, makes felt, forms it into a hood then shapes it on a hat block and "cooks" it for about 10 to 20 minutes in a low-temp oven to set the form. "Wool has a memory," she said.