Wednesday through to Thursday.
A large complex low is forecast to cross central New Zealand today (Wednesday) and early Thursday. North to northwesterlies with periods of heavy and possibly thundery rain are expected to affect northern and central New Zealand today, with southerlies and rain about the lower South Island.

The heaviest falls are expected about Clutha and Dunedin, where accumulations may reach 80 to 100mm today, which is a significant amount of rain for the area. In addition, persistent heavy showers and thunderstorms about Taranaki this morning and afternoon may to bring up to 70mm about northern areas, including the Mountain.

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June 2015 predicted to be cooler.

"A cooler than usual June looks likely for New Zealand," said MetService Meteorologist Georgina Griffiths. "Below average June temperatures are  expected this year - in sharp contrast to last June, which was the warmest  on record for New Zealand." While there will be weekly variation in temperatures, swinging between average and below average, the first and last weeks of June look particularly cold across large parts of the country.

Over the last month, El Nino has strengthened in the tropics, reaching levels not seen since 1997-98. The latest climate models predict a high chance (80-90%) that El Nino will continue through the rest of 2015. "Seas  in the New Zealand region are cooling off faster than usual, which is  consistent with changes we typically see here during an El Nino winter," said Griffiths. "Sea temperatures are important for us, because to a  certain extent they influence air temperatures in our coastal regions."

Certainly, some farmers will be looking for a break in the weather this June. It has been a sopping wet April and May between Taranaki and Wellington, as well as for the West Coast of the South Island. Paraparaumu experienced its wettest May on record, following on from its wettest April ever. In just two months, 453mm of rain has fallen there. To put that in perspective, that's nearly the same as the amount recorded at Westport over  the same time (477mm)! But that's nothing-Milford Sound has clocked up in excess of 1,700mm this April and May. In contrast, only 2.8mm of rain fell in Timaru in May (the fourth driest month on record there), while Oamaru received just 8.8mm.

During the first week of June, a major Low rolls across the country,bringing significant precipitation and strong winds to many parts of the country. "June starts pretty wet and wild, with the risk of extreme rain or  snow in the mix. But, as the month progresses, the weather is likely to  settle back to more typical early-winter patterns," added Griffiths. Rainfall for the remainder of the month looks closer to June normal for western regions, but normal to below normal for the north and east of both Islands.