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

Other days

lash

Lash Day
hannah

Hannah Day
one

One Day
my little pony

My Little Pony Day
first love

First Love Day
bow tie

Bow Tie Day
cuddle up

Cuddle Up Day
bonang

Bonang Day
carpenters

Carpenters Day
tulip

Tulip Day