The manager at Lake Tarawera's Landing Cafe Leanne Cunningham said they sold 190 litres of ice cream, or a month's worth, over the long weekend.
The monumental heat had brought on a monumental thirst and the cafe had its first-ever sell-out, running out of cookies and cream.
"We got in an order that lasted two days when usually it lasts about a month... that has never happened."
Cunningham said the line for ice cream had lately been out the door, and people would wait despite technical difficulties with the real fruit icecream machine.
Rainbow, goody goody gum drops and real fruit ice cream were particularly popular, but not as popular as the sell-out cookies and cream.
The heat had also caused more people to seek shelter in air conditioning and Rotorua Reading Cinema supervisor Hannah Panman-Coull said the heat had seats filled "more than usual for the middle of the day".
Panman-Coull said people had made an effort to head indoors to escape the heat.
Fire crews also braced themselves for more callouts as the Rotorua fire risk sat at high.
Yesterday about 3pm firefighters responded to a 50m powerline fire on State Highway 5 near Reporoa as the wires drooped from the heat.
Fire and Emergency New Zealand deputy principal of rural fire Jarron McInnes said fires were "certainly mounting up region-wide".
Fire and Emergency New Zealand assistant area manager Hamish Smit said it was important people remained vigilant.
Although there had been no large-scale fires, Smit said the combination of heat, drying ground and warmer minimum temperatures meant they expected an increase in callouts.
"Small fires become large fires very quickly in these extreme conditions. It's important the public feels comfortable to dial 111.
"Extreme weather has always happened but with the warming planet, the extreme weather is becoming more common."
Despite the higher temperatures, St John Rotorua had not responded to any heat-related callouts but remained on standby as the heatwave set in.
Heatwaves - Unusually hot weather over a region for at least two consecutive days - Can cause heat rash, sunburn, heat cramps, heat exhaustion or heat stroke - Prevent harm by staying out of the heat, limiting physical activity, adjusting work practices and drinking plenty of water Source: New Zealand Ministry of Health