dimout

“During World War II, the United States was adhering to a wartime "dimout" and in 1942 and 1943, there was no ball drop.”

The Huffington Post: Kate Kelly: The Times Square Ball Drop and the Story Behind It

“During those war years, New York was subject to a "dimout" of lights intended to protect the city from Axis bombings.”

The Huffington Post: The New York Public Library: Telling Time on New Year's Eve: Why the First Ball Was Dropped in Times Square

“Tradition took root and the ball has heralded a new beginning almost every year since - in 1942 and 1943, during World War II, the ball was temporarily put out of commission by a war-time "dimout.”

TIME.com: Top Stories