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

Other days

Carpenters Day

Healing Day

Cursing Day

Tell Ur Crush You Like Them Day

Chocolate Milkshake Day

Lisp Day

Lumpy Rug Day

Ponytail Day

African Immigrant And Refugee Hiv And Hep Awareness Day

Nail Polish Day