When will Election Day be, and how is it decided?

Explainer - Only one person can decide when Election Day 2026 is. How is it picked, and when is it likely to be?

Prime Minister Christopher Luxon is set to announce a date this week, continuing the tradition in recent years of setting a date at the start of the political year.

It's the starting gun that fires off a year-long sprint to determine the next Parliament, but how does the PM make this decision? Here's how it works.

Who decides when the election will be?

It's all down to the prime minister's call.

The Cabinet Manual which guides central government states that "the Prime Minister alone" has the right to advise the governor-general to dissolve Parliament and call a general election.

However, in the current National-led coalition government, Luxon would definitely be consulting partners New Zealand First leader Winston Peters and ACT leader David Seymour before announcing any date, said Massey University professor of politics Richard Shaw.

"The decision won't be one that the leader of the National Party takes without having had extensive conversations with the leader of the two coalition parties," he said.

"The prime minister will front this, but it will be an announcement on the part of the government."

Luxon on Tuesday morning would not be drawn on the exact date, but confirmed to RNZ he would be announcing the date this week.

"I will announce the election date, and that's just because that's been a strong convention in New Zealand."

When are they required to make that call?

They can pick a date any time, but an election has to be called before the end of the current three-year parliamentary term.

The last possible legal date for this year's election to be held is 19 December.

What can we expect? When could it be?

Several pundits are picking the election to be called for after the American mid-terms set for 3 November, which will be a key indicator for how US President Donald Trump's remaining two years in office will fare.

Saturday, 7 November has been mentioned most frequently as a likely date.

"My money is on" that date, Victoria University of Wellington professor of law Dean Knight said.

Every general election for the past 30 years since the introduction of MMP in 1996 has been sometime between September and November except for one.

How does a PM make that decision?

The date of an election is a symbolic beginning for the months of electioneering and campaigning ahead.

The Electoral Act 1993 requires polling to take place on a Saturday.

When choosing a date, prime ministers want to avoid things like public holiday weekends, major central bank decisions, the start of Daylight Savings Time or other major events. In 2011, Key made sure to pick a date after the Rugby World Cup final which was hosted in New Zealand.

"You narrow things down," Shaw said. "It's an art as much as a science."

"There are very few rules for how all this happens. It's largely vibes-based, really."

Are elections always about the same time?

It's pretty typical now for an election date to be named for Spring and to be announced early in the year.

While it's not required, Knight said that at this point, the early call is quite bedded in.

"I have no doubt that the practice that the prime minister announce the election date well in advance, in the first or second month of an election year, has now crystallised into a constitutional convention."

Prime Minister Jacinda Ardern announced on 19 January the 2023 election would be on 14 October, and in 2020 she announced on 28 January an election for 19 September.

Back in 2017, Prime Minister Bill English announced on 1 February the vote would be 23 September, while in 2014, Prime Minister John Key didn't announce until 10 March the 20 September election date. In 2011, Key announced the election on 2 February, and it wasn't held until 26 November.

"The rhythm of parliamentary terms means a general election for a full-term Parliament usually falls in October/November; an announcement in January/February gives folk 9 or 10 months' advance warning - unlike the old days when it was often only a couple of months' advance notice," Knight said.

Prime Minister Helen Clark tended to call elections later - not until June, July and September in 2002, 2005 and 2008, respectively. But that seems to have gone out of vogue.

"An early announcement, as seen in the last five elections, is no longer merely a good idea but is now obligatory and would be met with political heat if ignored," Knight said.

"You generally get a reasonably early announcement for all kinds of reasons, some of which have to do with stability and predictability," Shaw said.

Parliament typically runs for the entire three-year term, but there's actually no law requiring the election to wait until the term ends. An election can be called even earlier - what is known as a "snap" election. Perhaps the most famous snap election was Robert Muldoon's call in 1984 for a vote that was held one month later.

The only election in recent years that came far earlier than expected was the one Helen Clark called in 2002 for 27 July. Clark called that election in mid-June, after Labour's coalition with the Alliance party fell apart.

Once the election is called, it'll still be some time before the regulated period for election advertising begins - it runs the three months before the election date. Before the election, Parliament must officially dissolve and on Writ Day, the governor-general will issue formal direction to the Electoral Commission to hold the election.

This year, the election will take place under changes in the new Electoral Amendment Bill that passed Parliament just before Christmas. Among other things, it requires people to enrol at least 13 days before the election and ends same-day voter enrolment. The government said the bill would improve the timeliness, efficiency and integrity of elections, but the opposition said it would suppress voting.

Do other countries decide election dates like this?

It's fairly common in many parliamentary democracies, unlike places like America where the date of Election Day is always the first Tuesday after the first Monday of November (typically, around 2 to 8 November).

Australia, the UK and Canada all have similar processes where the PM must call an election before their term ends, or earlier if they want a snap election - sometimes to confirm a new leader's power base.

Last year, when long-standing Canadian PM Justin Trudeau stepped down, his replacement Mark Carney called a snap election for the very next month, which he easily won. Japan's new prime minister Sanae Takaichi, who just took office in October, has also called for a snap election as soon as February.

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