Oops, it doesn't look like 'dress like a muggle day' is a national day..

Other days

Appreciate Yaself A Lil Extra Day

African Immigrant And Refugee Hiv And Hep Awareness Day

Healing Day

Azonto Is Acceptable Day

Lost Sock Memorial Day

Promposal Day

Kiss A Brunette Day

Lash Day

Me Day

Lumpy Rug Day