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

Other days

coffee

Coffee Day
self care

Self Care Day
fiancee

Fiancee Day
china

China Day
buddy

Buddy Day
polyamory

Polyamory Day
pumpkin

Pumpkin Day
gum

Gum Day
bow tie

Bow Tie Day
frozen yogurt

Frozen Yogurt Day