And those numbers were stark. Labour's support dropped by five points in the Talbot Mills Research poll, and by six points in the Taxpayers' Union Curia poll.
It is now hovering around the 40 per cent mark.
The steep drop over the last month followed smaller but steady drops since the start of this year.
Last year's lockdowns saw her rise to hero status because they worked.
But this year's Delta lockdowns have delivered a different ending.
What will worry Ardern more than the drop in Labour's support is the drop in confidence in the Government's handling of Covid-19, because that speaks to a faltering in the trust in her.
Those rating the response as good has dropped from the 60s to 46 per cent. Those who think the worst is yet to come has spiked to 75 per cent.
That is the most urgent thing she needs to address.
The traffic lights system is yet to be tested, and there is some scepticism and wariness about the split between the vaccinated and unvaccinated.
It was said by Sir John Key that putting people into lockdown was the easy bit. Getting them out of it again was the hard bit. So it has proven.
It has been a winter of discontent for the country. Ardern has now promised summer, and she will be praying that the summer sun burns off the anger.
She simply cannot afford not to deliver on that promise now – even if it means making decisions she might not be comfortable with.
It has already forced her into taking a harder line on the unvaccinated than she might have been inclined to. She has also had to resist waiting until demographics such as Māori and those in rural areas get to 90 per cent.
Ardern will be looking to the polling fortunes of her counterparts in other countries, and hoping the anger will dissipate along with the restrictions.
In Australia, PM Scott Morrison fell to his lowest levels of support in August as the country groaned under lockdowns and travel restrictions. Confidence in his handling of the pandemic plummeted.
Australia's restrictions are now lifting, but other issues – including inflation – are hitting hard and Morrison is still struggling in the polls.
The difference between them is that Morrison faces an election next year. She has another two years. The other difference is the Opposition.
Morrison remains ahead as preferred PM, but his Coalition is being pipped by Antony Albanese's Labor Party.
The hope for Ardern here is that, however dented the faith in her might be at the moment, there are still no signs voters think anybody else is better equipped to do the job.
Labour's polling has dropped back down to pre-Covid levels.
But National's has not risen to its pre-Covid levels.
It continues to languish in the mid-20s, and has made little ground off the back of the rising discontent. Labour and the Greens are still 10 points ahead of the National-Act grouping.
Ardern has pointed to Covid-fatigue impacting on the mood of the country, and promised that summer would deliver a much-needed reprieve from it.
It will be a white-knuckle ride as the inevitable spread of the virus puts pressure on the health system, businesses get to grips with the reality of vaccine mandates, and Covid-19 deaths go up.
It is new territory, and Ardern has acknowledged there is uncertainty in what lies ahead.
On Tuesday, she uttered three words she rarely uses: "I don't know." That was when she was asked whether vaccine mandates would be a long-term thing for the country.
However, Ardern has waited for a higher level of vaccination than most other countries before easing up – that may have come at a political cost in the short term, but in the longer term it may pay off.
New Zealanders will nonetheless have to get used to having Covid-19 walking down the streets and on the beaches with them.
But three months of restrictions and disruption have well and truly made it clear the zero-Covid days of 2020 are now nothing more than a fairy tale.
Life with Covid will be more acceptable to people than it was last year.
