St. Patrick’s Day is observed on March 17 because that is the feast day of St. Patrick, the patron saint of Ireland. It is believed that he died on March 17 in the year 461 AD. It is also a worldwide celebration of Irish culture and history. St. Patrick’s Day is a national holiday in Ireland, and a provincial holiday in the Canadian province of Newfoundland and Labrador.
The actual color of St. Patrick is blue. Green became associated with St. Patrick's Day during the 19th century. Green, in Irish legends, was worn by fairies and immortals, and also by people to encourage their crops to grow.
St. Patrick did not actually drive snakes out of Ireland; the snakes represent the pagans that he converted to Christianity.
The very first St. Patrick's Day parade was not in Ireland. It was in Boston in 1737.
In Chicago, on St. Patrick's Day, the rivers are dyed green. Mayor Daley is also of Irish descent.
In Ireland on St. Patrick’s Day, people traditionally wear a small bunch of shamrocks on their jackets or caps.
Many people wear green on this holiday to avoid being pinched.
Many bars in the United States, and abroad, serve green beer to celebrate St. Patty's Day.
Oh and people like me... dress their pets up in festive attire to help spread the cheer!