Lutheran, Anglican, Orthodox and Catholic Christians celebrate the feast day of the Birth of St.John the Baptist on June 24.
a very popular event in the Ancien régime of France, and it is still celebrated as a religious feast day in several countries, like Denmark, Norway, Sweden, Finland, Estonia, Spain, Latvia and Lithuania.
Accordint to the Wikipedia, the tradition landed in Canada with the first French colonists. According to the Jesuit Relations, the first celebrations occurred on the banks of the Saint Lawrence River on the evening of June 23, 1636, with a bonfire and five cannon shots.[12] It has become a celebration of Canadien unity, especially since the end of the Lower Canada Rebellion.
LIke many national and ethnic holidays, it has become a reason to celebrate by getting wasted.