Jeenah Moon/Reuters
Former President Donald Trump's posters are displayed at his campaign headquarters in Urbandale, Iowa, on January 13, 2024.
CNN  — 

Donald Trump begins the last day of campaigning in bitter cold Iowa before Monday’s caucuses, boosted by new polling showing him with a dominant lead among Hawkeye State Republicans, as his closest competitors continue their jockeying for second place.

Trump leads the pack with 48% of likely caucus-goers naming him as their top choice, according to the Des Moines Register/NBC News/Mediacom poll, with former South Carolina Gov. Nikki Haley getting 20% and Florida Gov. Ron DeSantis at 16%

The poll’s release kicked off a frenetic final day ahead of what’s expected to be the coldest caucus on record, and Iowa’s iciest January day in at least five years, with wind chills as low as 40-degrees below zero. The frigid forecast, coming on the heels of a week of extreme weather, largely forced Republicans off the trail and onto Zoom calls and tele-town halls, creating at least one element of uncertainty in a slog of a campaign that Trump has always seemed destined to dominate.

“Our grassroots supporters have put us in position to win, and now we have to show up to Caucus for President Trump on Monday and get the job done,” Trump said in a statement late Saturday, after the poll’s release. “We have to show up.”

Questions and concerns over how the weather will affect voter turnout are looming over the final furlongs of the race for Iowa, which effectively began more than a year ago and have throughout appeared to be Trump’s to lose. It seems now that the only way he might would be if his backers took the result for granted and chose their warm living rooms over polar passage to the caucus sites.

The DeSantis campaign seized on that uncertainty in a late Saturday night message to supporters who might have felt stung by the latest horse-race numbers.

“Any pollster who tells you they know what turnout will be on Monday night given the historic weather conditions isn’t telling the truth,” the campaign said in a messaging memo, obtained by CNN, that described DeSantis’ get-out-the-vote organization as being “perfectly designed for the forecasted conditions.”

The Haley campaign framed it differently, touting their improved poll numbers and promising that, “despite the cold weather, on Monday, Iowans will have the first chance in the nation to voice their desire for a new generation of conservative leadership with Nikki Haley.”

“Thank you for coming out on this cold snowy day,” Haley told voters earlier Saturday in Cedar Falls. “This (election) comes down to a choice … You’ve got the opportunity to look back at the past and continue or go forward and start new.”

Trump was absent from the Hawkeye State for most of Saturday after canceling a number of in-person events due to the weather. But he will be on hand for a rally in Indianola on Sunday afternoon and is slated to host a teatime tele-rally with GOP state Rep. Bobby Kaufmann.

Like everyone else, Trump was thinking about the weather – and what it could mean for the caucuses – upon setting foot in Des Moines.

“I just landed in an airplane and it’s nasty out there,” Trump said, “I worry about (voters getting to their caucus sites), but at the same time, I’m watching even the newscast today, they’re saying the Trump voter has so much more spirit, dedication, they say they’ll walk over glass, that the Trump voter’s coming to vote.”

The former president, on this occasion at least, has the data to back up his claim.

Nearly 90% of Trump-backing likely caucus-goers say in the poll that they are extremely or very enthusiastic about voting for him. It’s a remarkable figure, befitting an incumbent president, and towers over his nearest rivals. Sixty-two percent of DeSantis backers feel the same way, while only 39% of Haley’s supporters in Iowa were excited about the prospect.

DeSantis’ Sunday schedule is the busiest of the top tier candidates. He’ll be on his “Never Back Down” super PAC’s “Countdown to Caucus” tour making four stops beginning in Dubuque, on the Mississippi River, before heading over to Cedar Rapids, taking a trip out to Sioux City, in the state’s conservative northwest, before ending in Ankeny, just outside Des Moines.

Haley too begins her Sunday in Dubuque. She then heads to Ames, home to Iowa State University – and some of the less conservative voters she’ll need to coalesce around her here and in coming contests  – before closing out the day in Adel.

Entrepreneur Vivek Ramaswamy is trying to outdo them all, with five stops listed on his itinerary. But the real excitement around his campaign, which registered 8% in the DMR poll, is how he will respond to a late barrage from Trump, whom Ramaswamy has defended on the trail as he tries to stake a claim with the MAGA faithful.

“Vivek started his campaign as a great supporter, ‘the best President in generations,’ etc. Unfortunately, now all he does is disguise his support in the form of deceitful campaign tricks,” Trump said in a post on his social media site. “Very sly, but a vote for Vivek is a vote for the ‘other side’ — don’t get duped by this.”

Trump also attacked Haley on Saturday night, his eyes already trained on the New Hampshire primary next week when she will try to solidify her place as the Republican Party’s alternative to Trump.

“I know Nikki very well. She was my ambassador to the United Nations and she had a lot of weakness, to be honest, she had a lot of weakness,” Trump said during his evening event. “I don’t think Nikki’s strong enough to be president.”

The former president also had some unkind words for President Joe Biden, hospitalized Defense Secretary Lloyd Austin and the judge overseeing Trump’s defamation trial, which begins next week.

More notable than that, though, was the rival who did not get much attention in Trump’s remarks: DeSantis.

The Florida governor entered the 2024 GOP presidential primary as the odds-on favorite to challenge Trump for the nomination. Now, on the eve of the primary season finally beginning, he’s become something of an afterthought.

Some of the underlying data in the DMR poll suggests he could outperform the baseline numbers, but even then, DeSantis will be campaigning over the next day like a man whose aspirations are very much on the line – along with a ticket to New Hampshire that could yet go unused.

This story has been updated.

CNN’s Jennifer Agiesta, Kate Sullivan and Veronica Stracqualursi contributed to this report.