Oops, it doesn't look like 'walk in a park day' is a national day..

Other days

lisp

Lisp Day
blanket fort

Blanket Fort Day
mean girls

Mean Girls Day
kale

Kale Day
pick me

Pick Me Day
boy friend

Boy Friend Day
bounce

Bounce Day
aloxolt

Aloxolt Day
comfy

Comfy Day
china

China Day