The mercury isn't the only thing registering as chilly this December. Relations between Mayor Bandon Johnson and a majority of the City Council are frigid as the two sides remain deadlocked on a key feature of Johnson's 2026 budget plan.

Much of the debate over the mayor's budget has centered on reimposing the so-called head tax, a proposal Johnson calls fair, but critics say is a job killer.

Initially pitched as a $21-per-employee per-month tax on companies with more than 100 employees, the mayor is now floating an alternative head tax plan to go after fewer companies. His amended head tax proposal would apply to companies with at least 500 employees, while raising the monthly per-employee tax to $33.

It's a hot potato in a frigid budget season at City Hall.

With less than a month left to pass a budget, a group of 26 aldermen has pitched an alternative plan, which would not include any head tax.

The mayor claimed when the city ended the original head tax in 2014, it didn't result in more jobs created, but alders said there is evidence that's not true, citing Bureau of Labor Statistics Data that a job boom did occur for several years after the head tax went away.

"We can't afford a head tax in any form. This is a hard stop," said Ald. Samantha Nugent (39th).

But the mayor has called his critics' alternative budget a nonstarter.

"Their proposal was $300 million short," Johnson said. "That's incomplete."

The mayor has vowed to veto any alternative budget that increases property taxes or the city's garbage fee, and the alders' counterproposal would nearly double the city's garbage fee. Johnson made it clear again on Monday he would not support the proposal to increase garbage fees.

"Find progressive revenue streams that allows for our budget to be balanced so that we don't continue to sacrifice poor and working people," he said.

Ald. Scott Waguespack (32nd) accused the mayor of finger-pointing.

"He has resorted to insults and attacks on those of us who have dared to call out the dangerous flaws in his irresponsible budget," he said. "We've done the work. The person who hasn't done the work and hasn't shown their work is the mayor."

The head tax, which the mayor claims will not cost jobs, was the focal point of a weekend budget session between alders and the mayor's budget team.

"The only person that was absent was the mayor. If we're going to make a deal, he needs to be at the table," said Ald. Gilbert Villegas (36th).

But Johnson said he's not the first mayor to send his budget director and chief financial officer to try to work out a budget deal with alders.

"My team is there. That's their job. That's their responsibility. They were there for nine hours. I'm updated all day every day on everything," Johnson said.

Johnson said he doesn't want to be the first Chicago mayor to see the city shut down over a budget impasse.

"No one wants it, but it's something that I'm working overtime to ensure that it doesn't happen," he said.

Some view the city's top executive using government shutdown talk as a political instrument as a Trump-like tactic.

"100 percent, and what you're seeing is both extremes that are in charge of their respective governments at the same time; the far left and the far MAGA. And it's my way or the highway, and that's just not how it works," Villegas said.

In a letter to alders on Monday, Johnson referred to the "Council Wars when Ald. Burke and Vrdolyak attempted to override Mayor Harold Washington's veto before compromising hours before the end-of-year deadline," in 1984, during a period of racially charged political infighting at City Hall, a reference that some alders were outraged by. 

"It's insulting this mayor would say things like that. We, and many more of us, the majority of the City Council have been working for weeks, trying to find alternative options," Ald. Matt O'Shea (19th) said.

City leaders have until the end of the year to sort out the budget impasse.