"It's going to be quite a warm, humid week though, for the north of the country with showers and high humidity," he said.
By Thursday, Mr Duncan said, winds would change to easterly and the big heat would return to the upper North Island.
"Victor itself is not going to bring a lot of weather to the country, but once it passes by the North Island it does change the weather pattern. There could be more humidity, more showers and more cloud for northern New Zealand for the next 10 days.
"It's good for the farmers and gardeners.
"They are very happy to hear rain back in the forecast."
Mr Duncan said people at the North Island's east coast beaches should be aware of the dangers from swells and big waves created by Cyclone Victor.
"I'm not sure if what happened in Bay of Plenty on Saturday was anything related to Victor with that boy drowning, but this is what we see almost every time there is a cyclone that is offshore.
"We almost always see a death or someone being swept out to sea.
"So we are trying to put out a message that even if the weather is really lovely at your camping ground or your beach there is quite a dangerous storm well out at sea that is changing the conditions on our east coast beaches," he said.
Mr Duncan said people should use commonsense and stay alert if they were on rocks, were looking after children or were not confident in the water.
Outlook
Auckland/Hamilton/Whangarei
Today: Sunny and hot. High 20s. 30C in some spots.
Tuesday: Cloud and showers. 27C.
Wednesday/Thursday: Warm and humid. Mid to high 20s.
Tauranga
Today: Winds and clouds pick up. 26C.
Tuesday: Cloudy. 25C.
Wednesday/Thursday: Hot and humid. 27C/28C.
