Overnight temperatures had been sitting just under 20C, about 5C over the usual January minimums.
Johnny Calley of Calley Homes said the heat was making life "extremely difficult" for builders.
"We've had a couple of staff down with heatstroke."
Staff were covering up, planning any work in direct sunlight for earlier in the day, and trying to stay in the shade.
Calley said the heat was the worst he had seen in years.
Last week Tauranga builder Tim Doddrell told NZME workers often had to sweat it out indoors as commercial building owners did not like to turn on air conditioning units during construction.
"If you're building in commercial buildings that are new with air con they won't put them on for you because they say the building work causes dust in the air con, which is rough as most new commercial buildings are built with no windows that can open," he said.
Other Tauranga tradies said they were starting earlier to beat the heat.
Andy Dwan, the owner of BOP Roofing Services, said he encouraged his staff to be on site working by 7am so they could leave at 3pm.
"Get it done and get out of there."
Ryan Watts, director of Electricians BOP, said temperatures in ceiling cavities could reach 55C, so that work was reserved for first thing in the morning.
"We can't stop doing our jobs."
Even some indoor workers cannot escape the heat. Luigi Barattieri of Papamoa's Bluebiyou said his kitchen staff were often working in 45C humid heat - but with hordes of hungry and thirsty people to serve, what else could they do?
"I have had many volunteers to tidy up the chiller."
Tauranga CBD Kathmandu assistant manager Belinda Farley said a chef picked up the last of their freezable cooling scarves on Saturday.
"We've had seven more inquiries today."
Sunshades for the beach were also sold out, and fold out chairs were heading the same way yesterday as people prepared to head to the cricket.
More than 5000 braved the heat to attend DinoFest at Sydenham Botanical Park, but how did the "dinosaurs" cope?
"The dinosaurs have been having lots of water and Frujus," event organiser Laurence Taylor said.
In Mount Maunganui, the college pool has seen double the number of swimmers from last year, Omanu Surf Lifesaving Club president Donal Boyle said.
The pool, which the club had been opening to the public between 11am and 4pm for $4 a head, was hosting about 50 swimmers a day, he said.
Tauranga residents have reported freezing filled hot water bottles, eating ice cubes and hanging ice packs on fans to stay cool.
Sunday's highs
Auckland - 28.5C
Hamilton - 29.7C
Tauranga - 26.5C
Wellington - 22.7C
Christchurch - 25.6C
Dunedin - 27.2C
Queenstown 29.7C
Source: MetService
