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

Other days

ruby

Ruby Day
comfy

Comfy Day
bow tie

Bow Tie Day
boyfriend

Boyfriend Day
slime

Slime Day
get funky

Get Funky Day
brow

Brow Day
china

China Day
stud

Stud Day
azonto is acceptable

Azonto Is Acceptable Day