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

Other days

comfy

Comfy Day
youth

Youth Day
self care

Self Care Day
nae nae

Nae Nae Day
my little pony

My Little Pony Day
ruby

Ruby Day
slime

Slime Day
cuddle up

Cuddle Up Day
boy friend

Boy Friend Day
girl friend

Girl Friend Day