Hold your hat over a pot of boiling water until it is damp and then put it on your head or on a foam head or hat stand in your size until it dries completely. The hat will shrink slightly. ... Wear your hat in the rain. As the hat dries, it will shrink down and shape to your head.

Do straw hats shrink over time?

Natural fibers in hats can cause gradual shrinking over time, especially if you ever have to wash it. Not to mention sweat, humidity, and weather all contribute to shrinking hat syndrome.

Do straw hats shrink or stretch?

They normally can stretch a hat another ½ to 1 size at most. So, you do need to pay attention to size when shopping for a hat; try the hats on. Only rely on hat stretchers for small size adjustments.