As it happened: Trump wins Iowa Republican presidential caucuses; Ron DeSantis comes in second

While US primaries resemble general elections (with day-long voting at polling places and the option of absentee or postal ballots), caucuses occur at a specific time and look more like neighbourhood meetings.

In Iowa – a predominantly white, rural state in America’s Midwest with high numbers of Evangelical Christians and farmers – they’re held in community rooms, churches and schools across about 1670 designated precincts.

The main purpose is to give party members a say in who they want in the White House, but it is also the first step in a months-long process to select delegates for the national party conventions later in the year, where the nominee for president and vice president will be announced.

The process is pretty straightforward: once participants have checked in, they elect a chair and a secretary to lead the meeting. After the American pledge of allegiance, a prayer and a few speeches on behalf of the candidates, they’ll get a blank slip of paper to write down their presidential preference.

The ballots are immediately tallied in the same room, read aloud and sent back to the state party. Republican officials say they expect results to start arriving about 8.30pm local time (1.30pm Tuesday AEDT) and most precincts will be reported by about 9.30pm.

It’s worth noting, however, that this year’s caucuses will focus solely on Trump and his Republican rivals. While Democrats will start to hold their caucuses on the same day as Republicans, the results won’t be known until March.

You can read more about the process here.

Good morning and welcome to our live coverage of the Iowa caucuses: the crucial event that kicks off the US election and will help determine who gets to run as the Republican candidate for the White House in November.

North America correspondent Farrah Tomazin is in the city of Des Moines, Iowa, in the US Midwest, where it is currently -18 degrees before you add in the wind chill factor. Republican presidential candidates spent their final day of campaigning while braving the cold and snow.

There are concerns that wind-chill temperatures of up to minus 34 degrees could end up impacting voter turnout at the caucuses – which are set to be the coldest on record.

Donald Trump is the overwhelming favourite to stake an early claim to the party’s 2024 presidential nomination and has urged Americans to get out and vote even if they are “sick as a dog” and end up dying.

“You’ve got to get out – you can’t sit home!” the former president told a packed room in Indianola, about 20 kilometres from the Iowan capital of Des Moines.

“If you’re sick as a dog, you say, ‘darl, I’ve got to make it’. Even if you vote and then pass away, it’s worth it.”