On election day, poll provider FiveThirtyEight suddenly named Vice President Kamala Harris as her favorite to win the White House for the first time since October 17th.

The race has long been neck-and-neck, with each candidate leading by razor-thin margins in the polls.

FiveThirtyEight had former President Donald Trump as the favorite to win for about two weeks until Monday, when it found that out of 100 simulations, Trump won 53 times and Harris won 47 times.

But in an Election Day update, Harris emerged as the favorite, winning 50 times out of 100, while Trump won 49 times out of 100.

The last time FiveThirtyEight viewed the vice president as the favorite to win based on this model, which uses polling, economic and demographic data, was on October 17, when it found that Harris won 52 times out of 100, while Trump Won 48 times out of 100.

The odds of there being no Electoral College winner are less than one in 100, the poll aggregator said.

Similarly, FiveThirtyEight founder Nate Silver, who is no longer associated with the site, technically named it for Harris. In his latest election forecast for FiveThirtyEight's “direct descendant,” the Silver Bulletin, he picked Harris as the favorite to win by a razor-thin margin.

Out of 80,000 simulations, Harris won 50.015 percent of the time, while Trump won 49.65 percent of the time, according to Silver's model. About 270 simulations resulted in a 269-269 tie in the Electoral College.

Silver warned in his Election Day newsletter: “When I say that the odds in the presidential race this year are as close to 50/50 as possible, I'm not exaggerating.”

“It’s not because my default setting is to hedge or just throw a bunch of extra uncertainty parameters into the model for no reason. This is my fifth presidential election – and my ninth general election overall, if you count the midterms – and there has never been anything like it.”

Newsweek emailed Harris and Trump's teams outside of normal working hours for comment.

The day before the election, Harris campaigned in Pennsylvania – with 19 electoral votes, he is the biggest prize among the battleground states that will determine the Electoral College winner. Trump held rallies in North Carolina and Pennsylvania before ending his campaign with a rally in Grand Rapids, Michigan, on Monday evening.

Newsweek has summarized here what the latest polls and forecasts say about both candidates' chances of winning the White House.