The weather will take a turn for the worse with the remnants of Cyclone June bearing down on the country.
The cyclone, which has come from New Caledonia, will bring rain and strong winds as it crosses the country.
MetService forecaster Elke Louw said the first part of the week would be miserable for many areas in the North and South Islands.
Rain and windy conditions would hit the upper North Island late today and spread to southern and central parts of New Zealand tomorrow.
While heavy swells along the east coast, from Cape Reinga to the Bay of Plenty, were also possible tomorrow, weather conditions were not expected to reach a level where weather warnings would be needed for affected areas, Mrs Louw said.
She recommended those keen to get back outdoors look forward to Friday, when dreary conditions were expected to clear for most of the country.
Rain is expected to hit Auckland this morning and continue through to tomorrow, but the low that was formerly Cyclone June will bring with it tropical warm humid air.
Eastern areas of the city will see the heaviest rain today.
"Rain will ease to showers tomorrow afternoon and the northeasterlies will die out, and we'll see southwesterlies developing," MetService forecaster Marylin Avery said today.
Temperatures in Auckland would initially drop as the tail-end of Cyclone June crossed the country but the northeasterlies would bring humid air from the tropics, with a high of around 23C today.
"So it'll be quite moist and warm and sticky," Ms Avery said.
The former cyclone is approaching the North Island this morning, and is expected to move southeast across the North Island tomorrow.
"But there's a rain band ahead of it, which is going to bring rain to most of the North Island today and probably some light rain or drizzle down the east of the South Island," Ms Avery said.
"As it goes by it's probably going to rain for most of the North Island and northern half of the South Island today [and] tomorrow, and then it moves away, quite rapidly, to the southeast followed by a disturbed southwest flow. By the end of tomorrow it should be off to the east of the country."
While rain is expected for most of the country, it is not expected to reach warning levels.
The heaviest rain is likely to be tomorrow in the eastern Bay of Plenty, Taranaki, Wairarapa, eastern Marlborough and the Kaikoura coast.
Strong or gale force winds are also expected as the low crosses the North Island, although the strongest winds are predicted to be out to sea.
"The strongest winds over land are probably going to be over Northland overnight and tomorrow, with the possibility of severe gales there," Ms Avery said.
• Auckland: Showers on Monday and Tuesday, easing by Wednesday.
• Hamilton: Scattered rain on Monday, easing on Tuesday later in the day.
• Wellington: North-westerlies, cloudy conditions on Monday. Rain on Tuesday with heavy falls possible.
• Christchurch: Cloudy with easterlies in the afternoon on Monday. Rain and drizzly conditions on Tuesday.
• Dunedin: Fine on Monday with cloudy, drizzly conditions developing in the afternoon and continuing through to Tuesday.