Donald Trump, Nikki Haley and Ron DeSantis campaign in frigid Iowa ahead of Republican caucuses

DES MOINES, Iowa -- The countdown to the Iowa caucuses is now in the homestretch.

In less than 24 hours, we should know which Republican will win the first contest in the nation for the 2024 presidential race.

Only Republicans are caucusing this time around. Democrats are simply mailing in their ballots.

With parts of Iowa still under blizzard warnings earlier Sunday and temperatures below zero, the weather was a factor.

Despite the cold, the top three Republican candidates were courting votes across the state, taking no chances on their caucus eve.

The Iowa caucuses are most critical for candidates not named Donald Trump. On Sunday, the Republican front-runner urged supporters, during his only in-person campaign stop, to make sure they caucus, not taking anything for granted.

"The big thing, and I say it at every speech - don't sit out on me. Even if you think we're winning by a lot, it doesn't matter. We have to get out and vote. And we're really setting the table for November by doing that, because we're in very good shape," Trump said.

The latest poll by the Des Moines Register, NBC News and Mediacom shows Trump with a commanding lead in Iowa with 48%, but Nikki Haley has moved into second place with 20%. Ron DeSantis has slipped to third with 16%.

With roads in many parts of the state making travel treacherous, Haley cancelled her first event, later urging supporters to help bring change to the party dominated by Trump.

SEE ALSO | Our Chicago: Iowa caucuses, primary process

"The only way we're gonna win the majority of Americans is if we have a new generational leader that leaves the negativity and the baggage behind and focuses on the solutions of the future," Haley said.

DeSantis, whose supporters were out knocking on doors in the bitter cold, is in need of a good showing in Iowa, having held more campaign events here than Trump and Haley combined.

"You're never gonna have an opportunity where your voice and your vote is going to pack as much of a punch as it will tomorrow night," DeSantis said.

A new ABC News poll shows President Joe Biden's approval ratings sinking to 33%, the lowest of any president in the last 15 years. Illinois Gov. JB Pritzker downplayed the poll's significance this early in the election season while speaking on ABC's This Week.

"This battle hasn't even been joined yet. You've got a bunch of Republicans, MAGA Republicans, espousing things that are not good for the American public that are on the stage now, and not until they choose a nominee will we truly be in this battle," Pritzker said.

The Iowa GOP downplayed the brutal weather and sub-zero temperatures, but admitted it could impact turnout.

"Iowans are used to difficult weather. We've had caucuses in bad weather before. I think turnout is going to be good. Of course, it might impact it somewhat and it might have different impacts on different campaigns," said Iowa Republican Party Treasurer David Barker.

Just before ABC7 Chicago Political Reporter Craig Wall's interview with Barker, his phone rang, and he excused himself, saying he had to take the call.

It turns out it was Trump calling to make sure that party leaders had everything ready for Monday's caucuses.