MetService said the warm spring sun should continue for at least another day.
Meteorologist Stephen Glassey said while this morning had started a little on the cooler side, things were looking up.
Christchurch was expected to push 20C on a largely fine day. Auckland started the day with a slightly warmer low of 7C, but was expected to reach just 15C. It was expected to be a sunny day with a few light winds.
Down south things weren't looking as great, with the first of this week's rain expected to touch down in Dunedin.
Glassey said the sun was going to go back behind the clouds again for a bit with rain expected to reach the south early in the week.
He predicted the weather front would bring rain to the south and west of the South Island today.
"The front is also expected to bring showers to parts of the North Island from Tuesday, mainly in western areas," Glassey said.
"On Friday a strong north to northwest flow develops over the country, spreading rain to most places."
Last week had many reaching for their winter woollies again as sub-zero temperatures left a fresh dumping of snow in areas around the country and kept the temperatures in many other parts in the chilly single digits.
Over the weekend many people around New Zealand took advantage of the brilliant sunshine and warmer temperatures with an outdoor jaunt to bask in the rays.
On Auckland's North Shore, hundreds took part in the annual marathon that kicked off early yesterday morning, from Takapuna beach, and ran till midday.
