El Nino conditions in the equatorial Pacific Ocean are set to continue over the next three months and affect the New Zealand summer – that's the message from the National Institute of Water and Atmospheric Research.

The current event is slightly weaker than the 1997/98 El Nino, which is the strongest since 1950 at this stage, but it is expected to intensify further and peak during the summer months.

Photo: File.

For November 2015 – January 2016, above normal pressure is forecast to the north and west of New Zealand, while below normal pressure is expected to the south of the country.

This circulation pattern is likely to be accompanied by anomalous west-southwesterly wind flows – a clear signature of El Nino conditions.

Sea surface temperatures are forecast to be normal or below normal to the west of the country, and below normal to the east of New Zealand.

Temperatures are equally likely to be average or below average for the north and east of the North Island, and most likely to be near average for the east of the North Island and north of the South Island.

Below average temperatures are most likely for the west and east of the South Island.

In Northland, Auckland, Waikato and the Bay of Plenty, temperatures are likely to be near average or slightly below average, while there is a 50-55 per cent chance that rainfall, soil moisture levels and river flows will be below normal.