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

Other days

gum

Gum Day
donate your hair

Donate Your Hair Day
aloxolt

Aloxolt Day
slime

Slime Day
lash

Lash Day
lost sock memorial

Lost Sock Memorial Day
bonang

Bonang Day
cuddle up

Cuddle Up Day
first love

First Love Day
artists

Artists Day