NEW YORK - It's a time-honoured tradition, the show must go on.

But on Broadway, snow or even merely the report of blustery winter weather can affect how plays and musicals do at the box office.

"People in Manhattan who are shrewd can probably get into anything they want," Howard Sherman, executive director of the American Theatre Wing, said Wednesday as more than flurries swirled through Times Square.

Theatre producers -- by tweeting, on Facebook and with email blasts -- reacted quickly to news of inclement weather on what is a two-performance day for most shows.

"It's kind of like a bonus day (for theatregoers)," said Sue Frost, a producer of "Memphis."

"You've got time on your hands you didn't know you had. What better thing to do than slush down the street and go see a Broadway show."

Many offered discount tickets to fill empty seats. Last Saturday's monster snow storm that buried Washington affected theatre in New York, even though the snow never really amounted to much in Manhattan or in most of its suburbs, despite advance reports on television news.

Weekly grosses slipped for most shows (in some cases a lot), primarily because of a miserable business Saturday, the most popular day for theatregoing.

"It was a nonevent as snow goes but it stuck everybody at home and that's very frustrating," Frost said.

Added Sherman, "People were scared away at a time of year when a significant majority of business is spur-of-the-moment. These forecasts that are so devastating can wipe out (business). . . . Every show got hurt unless they had a fantastic advance. And we didn't get snow."