Summer is likely to be warmer, drier and less windy than usual, increasing the risk of sunburn as people make the most of the balmy weather.
James Renwick, from the National Institute of Water and Atmospheric Research (Niwa), said after a warmer than average spring, the east of the North Island, including Hawke's Bay, was likely to experience above average summer temperatures and normal or less than normal rainfall.
The warm, settled conditions may be perfect beach-going weather, but Sarah Helliwell, from Hawke's Bay's branch of the Cancer Society, said there was no need to wait until summer to start applying the slip, slop, slap and wrap message.
It was not the heat that burned, but the Ultraviolet Radiation (UVR), which occurred even on cloudy and cool days. UVR levels increased throughout spring and often caught Kiwis unaware.
Miss Helliwell said children especially needed to be sunsmart.
Outdoor workers were also susceptible, although the sunsmart message was for everyone, including those with naturally dark skin, she said. And there was no such thing as a safe tan.
"When you get a tan it's literally skin damage, so the best way to [get a bronzed look] is to fake it," Miss Helliwell said.
Sunsmart spokesperson Wayde Beckman summed up the sun-care advice: "We need to slip into the shade, slap on a hat, slop on plenty of broad spectrum SPF30+ sunscreen and wrap on a pair of sunglasses, especially between 11am and 4pm," he said.
Skin cancer was the most common cancer affecting New Zealanders.
National rates for melanoma were among the highest in the world.
About 250 New Zealanders died from melanoma and 2000 new cases were diagnosed every year.