Donald Trump may be behind in most polls, but one veteran New York prognosticator still predicts he will win come Election Day.

“I think he was the strongest candidate in the primaries and that he will prevail,” Helmut Norpoth, a political science professor at SUNY Stony Brook, told The Post on Monday, even as the RealClearPolitics average shows the Republican candidate trailing Democrat Hillary Clinton by 6.1 percentage points.

Norpoth developed a model that, applied retroactively in earlier races, would have correctly predicted the winner of every presidential election since 1912 — with the exception of 2000, when predicted winner Al Gore barely lost to George W. Bush.

The model looks at which of the candidates performed better in the primaries and caucuses and concludes that the stronger performer there will enter the White House.

While the political ground has shifted dramatically since Norpoth first made his call, he’s not budging on the outcome.

“The model predicted a Trump win in February and nothing has changed since then. Whatever happens in the real world doesn’t affect the model,” he said.