Oops, it doesn't look like 'adopt a groundhog day' is a national day..

Other days

hoodie

Hoodie Day
carpenters

Carpenters Day
artists

Artists Day
lumpy rug

Lumpy Rug Day
nae nae

Nae Nae Day
singles

Singles Day
nail polish

Nail Polish Day
one

One Day
camera

Camera Day
buddy

Buddy Day