Oops, it doesn't look like 'sonic costume awareness day' is a national day..

Other days

frozen yogurt

Frozen Yogurt Day
prosecco

Prosecco Day
youth

Youth Day
one

One Day
singles

Singles Day
buddy

Buddy Day
me

Me Day
self care

Self Care Day
ruby

Ruby Day
african immigrant and refugee hiv and hep awareness

African Immigrant And Refugee Hiv And Hep Awareness Day