Current indications are that this summer will be a bit more “summer-like” than last summer.

The 3 month forecast from NIWA points to a lack of El Nino or La Nina as being a major player in our weather for the upcoming season with a more south-westerly flow expected over the country. That flow will be the result of lower than normal pressures that are expected to develop southeast of the Chatham Islands.

Summer rainfall is expected to be near average for most of the country. The exception being the northern and eastern North Island where rainfall could end up being a bit below average.

Summer soil moisture levels and river flows are likely to be below average in the north and east of the North Island. Average levels are expected for the southwest North Island as well as the upper tip of the South Island. Average to below average levels are expected for the remainder of the Mainland.
 
Summer temperatures are likely to be near average or below average in western areas of both Islands, as well as the east of the South Island. Temperatures should be about average for the rest of the country.

Sea surface temperatures around New Zealand are currently about 1 degree colder than average, and are expected to continue below average over the summer period.
For this tropical cyclone season (November – April), the risk of an ex-Tropical Cyclone approaching New Zealand is expected to be near normal. On average, one ex-Tropical Cyclone nears New Zealand during the season.

Here’s a look at the regional predictions for the next three months:

Northland, Auckland, Waikato, Bay of Plenty
Summer temperatures are likely to be in the near average range. Seasonal rainfall totals are likely to be near normal or below normal, while summer soil moisture levels and river flows are projected to be below normal for this time of year.

Probabilities are assigned in three categories: above average, near average, and below average. The full probability breakdown is:
   Temperature    Rainfall    Soil moisture    River flows
Above average    15   20    10   10
Near average    50   40    40    40
Below average    35   20   50   50

Central North Island, Taranaki, Wanganui, Manawatu, Wellington
Summer temperatures are equally likely to be near average or below average. Rainfall, soil moisture levels and river flows are all likely to be in the near normal range for the season as a whole.

Probabilities are assigned in three categories: above average, near average, and below average. The full probability breakdown is:
   Temperature    Rainfall    Soil moisture    River flows
Above average    10   20   10   10
Near average    45   50   50   50
Below average    45   30   40   40

Gisborne, Hawke’s Bay, Wairarapa
Seasonal temperatures are likely to be in the near average range. Summer rainfall totals are likely to be near normal or below normal, while soil moisture levels and river flows are projected to be below normal for this time of year.

Probabilities are assigned in three categories: above average, near average, and below average. The full probability breakdown is:
   Temperature    Rainfall    Soil moisture    River flows
Above average    15   20   10   10
Near average    50   40   40   40
Below average    35   40   50   50

Nelson, Marlborough, Buller
Summer temperatures are likely to be near average. Seasonal rainfall totals, soil moisture levels, and river flows are also all expected to be in the near normal range.

Probabilities are assigned in three categories: above average, near average, and below average. The full probability breakdown is:
   Temperature   Rainfall    Soil moisture    River flows
Above Average   15   20   10   10
Near average    50   50   50   50
Below average    35   30   40   40

West Coast, Alps and foothills, inland Otago, Southland
Summer temperatures are likely to be near average or below average. Seasonal rainfall totals are likely to be in the near normal range, while summer soil moisture levels and river flows are equally likely to be in the normal or below normal range.

Probabilities are assigned in three categories: above average, near average, and below average. The full probability breakdown is:
   Temperature    Rainfall    Soil moisture    River flows
Above average    10   25   20   20
Near average    45   45   40   40
Below average    45   30   40   40

Coastal Canterbury, east Otago
Summer temperatures are equally likely to be near average or below average. Seasonal rainfall is projected to be near normal, while summer soil moisture levels and river flows are equally likely to be in the normal or below normal range.

Probabilities are assigned in three categories: above average, near average, and below average. The full probability breakdown is:
   Temperature    Rainfall    Soil moisture    River flows
Above average    20   25   20   20
Near average    40   45   40   40
Below average    40   30   40   40


By NIWA, WeatherWatch.co.nz
http://www.weatherwatch.co.nz/content/neutral-pacific-could-mean-a-warmer-and-drier-summer-nz