Some of those working for earthmoving company Maungatua Contracting suffered heatstroke after toiling in the unrelenting Central Otago heat.
And this week, it will be another stinking hot day at work for project manager Kane Duncan's team.
But Duncan isn't expecting a repeat of heatstroke symptoms that struck some workers in December.
They had measures to combat the heat, even if some people learned the hard way about following advice to drink plenty of water.
"You only do it once, ay," Duncan told the Herald on Sunday.
It's been a thumper of a summer — and a potential record-breaker with January likely days away from being the warmest month in New Zealand since records began in 1909 — with the heat arriving early and fiercely in November and barely releasing its sweaty grip since.
But early this week could be the fiercest of all - including the potential for the heat to reach 40C down south.
Wanaka heading for 34C, Alexandra 35C - Metservice
Metservice meteorologist April Clark said nor-westerly winds and clear skies would combine to bring hot weather to the eastern and inland South Island tomorrow and Tuesday.
The southern part of the island, in areas such as Central Otago, would be hottest tomorrow; on Tuesday the worst of the heat could move further north, to areas such as inland Canterbury, Clark said.
After toppling its record with 35.2C, Wanaka, where Maungatua Contracting provides civil construction services, is forecast to reach 34C tomorrow and 33C the day after.
The Central Otago tourist town is in the middle of an official heatwave, considered to be when the daily maximum temperature is at least 5C higher than the average maximum for five consecutive days. Wanaka's average maximum is 24C.
Duncan said they provided water, sun protection and set up a marquee for some tasks.
Workers also stayed off high intensity jobs in the hottest weather. And there was one benefit to starting at dawn to avoid the heat.
"Quite a few guys knock off early and go for a swim."
'We're in a desert'
Fellow Central Otago heat trap Alexandra will be even hotter, with a pair of 35C highs forecast tomorrow and Tuesday.
Breen Construction health and safety manager Chris Lambeth said they used shadecloth, wide-brimmed hats and crystal-filled cooling scarves and vests.
At Nichol's garden centre in Cromwell, 30km northwest of Alexandra, assistant manager Bev Campbell rotates staff to ensure none are too long outdoors.
Hats, sunblock and ice-blocks also eased the pain.
For the plants, it was just water, water and more water.
"We're in a desert and we're furiously trying to keep plants alive."
This week, a woman in her 60s with multiple sclerosis died in Christchurch from hyperthermia - when the body becomes dangerously overheated. The death prompted a warning from the Chief Coroner to others who have conditions that mean their bodies struggle to regulate temperature.
Productivity expected to slow
Christchurch will also be affected by this week's heat, with a high of 33C expected on Tuesday. Other eastern centres, and their corresponding inland areas, will also feel the heat that day, with 32C forecast in Blenheim and 34C in Timaru.
David Wilson, the chief executive of civil construction and maintenance company Sicon, said they stopped work, or moved workers out of direct sunlight, once temperatures topped 30C.
The company employs around 200 people on jobs between South Canterbury and Hurunui.
He was aware of one work stoppage this summer.
Longer breaks and a dose of understanding were also employed on hot days, he said.
"We just understand productivity might slow up."
Niwa staff said this week the central South Island settlement of Waiau reached 37C on Thursday and highs were likely to rise to the upper 30s and nudge 40C in eastern districts on Tuesday.
Clark said with Alexandra due to reach 35C, an inland area could hit 40C.
"I wouldn't say for sure, but there's a chance."
Hot air coming from Australia and the Tropics
WeatherWatch head analyst Philip Duncan was skeptical of Niwa's claim. The nor-wester which delivered a scorching February day in 2011, when Timaru topped 40C, came direct from Australia.
"This is a hot airflow that's partially coming out of Australia and partially coming out of the tropics, so I think from what I'm looking at highs in the late 30s are definitely possible.
"If I'm a betting man I don't think we'll break a record, but I do think we're looking at a very hot spell of weather on Monday and Tuesday and it all depends on the conditions where you are."
New Zealand's hottest recorded of temperature of 42.4C occurred in Rangiora, north of Christchurch, in February 1973.
The North Island notched up its highest temperature, 39.2C in Ruatoria, on the same day.
Whether that or even the 40C mark was threatened depended on the timing and angle of the wind, whether the sky was clear and whether that all occurred at the same time in the middle of the afternoon, Duncan said.
His top picks for top temperatures would be somewhere in either South Canterbury or Central Otago.
And while northern parts of the country will not be as hot, high humidity in places such as Auckland will cause discomfort.
Flooding possible late this week
Meanwhile, mother nature may have another card up her sleeve for Kiwis this week, with a tropical storm potentially delivering flooding late on Thursday and Friday.
The north and west of both islands were most at risk, and a potential clash with the next super moon could be a problem, he said.
"So with strong northerlies, and a low coming in, and heavy rain, and a super moon and king tides, there's a chance of coastal flooding."
Parts of eastern Auckland and the Coromandel have already been badly affected by coastal inundation this year, after heavy rain and king tides combined to damage roads, homes and businesses three weeks ago.
Beat the heat
1. Drink plenty of water throughout the day.
2. Put your sheets in a plastic bag and then into the freezer before using them for bed.
3. A hot water bottle filled with cold water and put in the freezer can also be used to cool feet.
4. Close curtains and doors during the day to keep the heat out.
5. Put a bowl of ice in front of your fan.
6. Have a cool shower and then wear a damp T-shirt to bed.
7. Stay off the booze - it warms the body.
8. Pets get hot too - a haircut can help and/or toys and treats in a frozen bowl of water will entertain them and keep them cool.
9. Book a winter escape to Russia.
10. Go for your dream job in Antarctica - the forecast high today is -6C.
High NZ!
Today:
Whangarei: Sunny, chance afternoon/evening shower. 26C.
Auckland: Partly cloudy, chance shower. Becoming fine in afternoon. 29C.
Hamilton: Morning cloud clears. Chance afternoon/evening shower. 29C.
Tauranga: Morning cloud, then fine. 27C.
Whitianga: Few showers clearing, fine afternoon. 25C.
Wellington: Morning and evening cloud, otherwise fine. 25C.
Nelson: Fine. 27C.
Christchurch: Cloud morning and night, otherwise fine. 27C.
Dunedin: A few showers in morning, chance thunderstorm from afternoon. 23C.
Wanaka: Fine, but chance afternoon/evening shower. 32C.
Alexandra: Fine morning, few showers and chance thunderstorm from afternoon. 30C.
Queenstown: Fine, chance shower afternoon/evening. 29C.
Tomorrow:
Whangarei: Cloudy periods, chance shower. 26C.
Auckland: Morning and evening cloud, otherwise fine. 29C.
Hamilton: Fine, some evening cloud. 30C.
Tauranga: Morning cloud, then fine. 27C.
Whitianga: Morning and evening cloud, otherwise fine. 25C.
Wellington: Morning cloud, then fine. 27C.
Nelson: Fine. 26C.
Christchurch: Cloud morning and night, otherwise fine. 25C.
Dunedin: Cloud morning and night, otherwise fine. 27C.
Wanaka: Morning cloud, then sunny. 34C.
Alexandra: Morning cloud then fine. 35C.
Queenstown: Morning cloud, then sunny. 31C.
