'Changeable' weather during month of May

Weather reports predict that next week will be stormy and wet for most of the country. Photo / Jose Antonio Maciel, Getty Images

A mixed bag of weather has been forecast for the month ahead as New Zealand charges into winter.

Meteorologist Georgina Griffiths said the country was due for some "changeable" weather in May following a warm but unpredictable April.

"The first weekend in May is forecast to be settled and dry, but active lows over the Tasman Sea soon bring in some rough and tumble weather next week," she said.

"Next week is signalled as stormy and wet for most of the country, with an elevated risk of extreme rainfalls in western parts of both Islands, as well as for Nelson."

Temperatures in the first half of the month were likely to swing from one extreme to the other, Ms Griffiths said, before settling to cooler temperatures.

"After unseasonably mild northwesterlies next week, a rapid change to unusually cool conditions is expected by mid-month. Eastern regions will experience the largest extremes in temperature in May," she said.

Above normal rainfall was expected for the western South Island, Nelson, and Taranaki to Wellington while parts of the North Island were expected to have a "drier than usual" month.