Don't forget to wear green today.
Saint Patrick's Day, or the Feast of Saint Patrick (Irish: Lá Fhéile Pádraig, "the Day of the Festival of Patrick"), is a cultural and religious celebration held on 17 March, the traditional death date of Saint Patrick (c. AD 385–461), the foremost patron saint of Ireland.
On St Patrick's Day it is customary to wear shamrocks and/or green clothing or accessories (the "wearing of the green").