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

Other days

pumpkin

Pumpkin Day
brow

Brow Day
hoodie

Hoodie Day
polyamory

Polyamory Day
tell a fairytale

Tell A Fairytale Day
lost sock memorial

Lost Sock Memorial Day
lumpy rug

Lumpy Rug Day
cat girl

Cat Girl Day
ruby

Ruby Day
bow tie

Bow Tie Day