Why do hockey announcers announce One minute remaining?

Answer 1

The announcers in a hockey game announce the last minute of play of a period as warning for the players. It is like a two minute warning in football.

Answer 2

its the rule of all pro hockey games. and to let the players know theres only one minute left in the end of the period.. why else?

Answer 3

So that people know how much time is left in the game. Also probably to let the players try harder to catch up to the winning team.