Former President Bill Clinton saw U.S. voter anger brewing.

In an interview with CNBC's "On the Money," Clinton said a few years ago he shared with his wife — former Secretary of State and current Democratic nominee Hillary Clinton — his view of the mood of the electorate.

"Way before Hillary declared, I said you've got to get prepared for this," the 42nd president told CNBC at the Clinton Global Initiative, held in New York City.

"There's a lot of populism, because there's a lot of road rage. People believe the political and economic order have let them down."

Clinton called his wife "a sort-of 'answers person' not an 'anger person.' I mean you feel anger, but, you've got to be yourself," he said. "Just go out there and try to be the grown-up in the room."

He predicted Vermont Sen. Bernie Sanders would "do well in the primary." And while Clinton "didn't know Donald Trump would be the Republican nominee," he thought he would "get a lot of votes."

The former Arkansas governor, known as a canny politician, said he "wasn't surprised" by the early primary success in many states by both Democrat Sanders and Republican Trump. Both candidacies were driven by voter anger, something he recognized because "I just saw it happening other places."

In Europe, Clinton told CNBC, he witnessed "in the last year and a half, the tide of sort of xenophobic nationalism doing well in the parliamentary elections in Germany and France."

He mentioned the Brexit vote in the United Kingdom as another example. In June, a voter referendum passed in Britain for the country to exit the European Union. The result was 52 percent to leave, while 48 percent voted to remain.

In that case, Clinton said "voter turnout was what made the difference. The actual number of people who wanted to stay (in the EU) was slightly greater than the people who voted to go. But the people who voted, voted to go."

He echoed the post-mortem analysis of the Brexit vote, which was divided by regional, financial and age differences. "Urban people, young people in areas like Northern Ireland and Scotland, they vote to stay and England and Wales. The rest of England, non-urban England and Wales, vote to go."

With the first Clinton-Trump debate scheduled for Monday, Clinton had some advice for the Democratic nominee.

"Hillary's got to bank on the fact that a lot of people will be watching the last debate and just go out there and talk to people," Clinton said. "And not be affected by all the meanness and all this stuff that we've seen."

As for the mood of voters during the final weeks, Clinton believes the anger level has changed.

"Everybody's kind of settled down, I think now they just want to settle down the last month and half," he said. "Take a good look at this, make a good decision."

Clinton shared some mixed feelings about the choices the American people will make when they go to the polls on Nov. 8.

"I still believe that in the end they'll choose answers over anger, and empowerment over resentment. Unity over division and bridges over walls. But they may not," he said.

"And it's up to our fellow Americans, they can choose whatever they want."

"On the Money" airs Saturday on CNBC at 5:30 am EDT, or check listings for air times in local markets.