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

Other days

buddy

Buddy Day
ponytail

Ponytail Day
lash

Lash Day
carpenters

Carpenters Day
bounce

Bounce Day
pumpkin

Pumpkin Day
blanket fort

Blanket Fort Day
tulip

Tulip Day
self care

Self Care Day
slime

Slime Day