New York once had a crazy moving day like Sept. 1 in Boston. It took a world war to end it.

New York City once had a crazy moving day like Sept. 1 in Boston. It took a world war to end it.

Decades ago, the city suffered as most apartments turned over May 1. The date in New York, like similar popular move-in times in Chicago, is believed to stem from traditions brought by European settlers.

Then came an international upheaval.

“World War II served as a major catalyst for the end to the moving day phenomenon in New York,” said Aleksandr Gelfand, who researched the issue for a project at the Baruch College of the City University of New York. “With many of the men engaged in the moving industry gone to serve overseas . . . it diminished the ability to move en masse for the duration of four years.”

A subsequent housing shortage, caused in part by veterans flooding back home, also played a role, Gelfand said. Rent control and other housing regulations also further reduced the phenomenon by deterring moves, he said.

And as the city’s population reached a critical mass, “people looking to move were hit by diminishing returns,” Gelfand said. “There simply weren’t as many tempting options as in the past.”

Now, apartment turnovers are much more spread throughout the year in New York.