Presidential historian Allan Lichtman dismissed the notion of an October surprise impacting next month's general election, calling it a "huge myth," while holding steady that Democrat Kamala Harris will win the White House on Nov. 5.

Lichtman, known as the Nostradamus of U.S. elections because he has correctly predicted the outcome in 9 of the past 10 presidential races, made the remarks in a Monday interview on NewsNation's "Cuomo."

Using his 13 keys based on governance, Lichtman on Sept. 5 predicted Harris to defeat Republican nominee Donald Trump. With Harris winning 8 of the 13 keys, his prediction is locked in, he said.

"I don't change my prediction in response to the polls," Lichtman told show host Chris Cuomo in response to a question about polls showing Trump and Harris neck and neck.

"My system is based upon the fundamental forces that drive elections," Lichtman, a distinguished professor of history at American University in Washington, D.C.

"It's governing, not campaigning, that counts. This whole idea of an October surprise is a huge myth. I've always made my predictions before [October] and I never change them."

Lichtman, who predicted Trump to defeat Hillary Clinton in 2016, cited the "immense" surprise of the "Access Hollywood" tape that came out in October of that year that had the pundits saying Trump was dead in the water. They urged Lichtman to change his prediction.

"I didn't, and I was right," he told Cuomo.

Lichtman's prediction came out five days before the presidential debate between Trump and Harris on Sept. 10, and he told Newsmax the day after that the debate was "irrelevant."

"I deliberately issued my prediction that Kamala Harris will become the first woman president of the United States … before the debate because I wanted to make the point that it's governance, not campaigning, that counts. And my predictions do not vary depending on the day-to-day events of the campaign," Lichtman told Newsmax then.

The only election that Lichtman got wrong was the 2000 race between George W. Bush and Al Gore, which came down to a Supreme Court ruling on the recount in Florida one month after the election.

• Allan Lichtman to Newsmax: Debate 'Irrelevant' on Prediction
• Election Nostradamus: Harris Will Defeat Trump