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

Other days

lisp

Lisp Day

Me Day

hot chocolate

Hot Chocolate Day

african immigrant and refugee hiv and hep awareness

African Immigrant And Refugee Hiv And Hep Awareness Day

offer

Offer Day

singles

Singles Day

bow tie

Bow Tie Day

special education

Special Education Day

self appreciation

Self Appreciation Day

ormille

Ormille Day