New Zealanders are being urged to be extra vigilant with sun protection, with ultra violet radiation (UVR) levels hitting their peak in January.
UVR regularly reached extreme levels at this time of year, National Institute of Water and Atmospheric Research's (Niwa) Richard McKenzie said today.
Even mild sunburn could lead to skin cancer later in life, he said.
"UVR is strongest in New Zealand during the school holiday period - at exactly the time when people tend to be outside more than usual.
"Levels of UVR rise as the sun gets higher in the sky. They're at their highest between 11am and 4pm, and peak at around 1.30pm."
He urged people wanting to get outside to wait until a bit later in the day.
"At 4pm the temperature is often just as high but UV levels are much lower. So have your lunch, have a siesta and then have your swim at the beach."
Health Sponsorship Council's SunSmart manager Wayde Beckman said it was important for people to avoid getting sunburned.
"Always make sure you and your family are sun safe. Sunburn is painful and unpleasant when it happens but, worst of all, it could pose a serious health risk years down the track."
Sunscreen was the last line of defence and should not be used as a means of staying out in the sun longer, Mr Beckman said.
"No sunscreen will completely shield you from the effects of UVR. It's especially important to seek out shade at the time of day when radiation levels are at their strongest."
He said people out in the sun should wear sun protective clothing (shirts with collars and long sleeves), a broad-brimmed hat, sunglasses and sunscreen on exposed skin.
NZPA