NIWA's climate outlook for the next couple of months shows the Bay of Plenty may continue to dry out, with warm temperatures and average or below average rainfall.

Drought indicators, soil moisture and river flows are most likely to be below normal for the north of the North Island and about equally likely to be normal or below normal for the east and west of the North Island and east of the South Island.

In the north and west of the South Island, normal soil moisture levels and river flows are most likely, given a 45-50 per cent chance.

New Zealand sea surface temperatures are expected to be near average or above average over the next three months.

On the percentages the air temperatures are given a 40 per cent chance of being near average and a 40-45 per cent chance of being above average for the north and east of the North Island.

There's a 40 per cent chance of near average temperatures being most likely for the remainder of the country.

Rainfall totals are about equally likely to be near normal with a 40 per cent chance, or with a 40-45 per cent chance of being below normal for all North Island regions.

The North of the South Island has a 35 per cent chance of below normal rainfall, while near normal rainfall is most likely for the east and west of the South Island. Missing from the three month climate forecast is the wind factor.

NIWA forecaster Ben Noll says the summer is still El Nino – Southern Oscillation neutral meaning meaning high pressure systems tend to be favoured to the west of New Zealand and the low pressure systems to the east of the country.

'And then you have those two working together as cogs. Around high pressure you have the counter clockwise airflow and around low pressure you have the clockwise airflow, that has created an anomalous southwesterly through the first month, say eleven days of summer here.

'That's also going to be a cool flow but in the bay of plenty since you have a lot of mountain ranges off to your south and east when you do have those westerly flows it can often be a bit warmer right along the shoreline and the coastline there in the bay of plenty.”

NIWA's December figures show the country was cool and dryer in spite of more sunshine.

Air temperatures were below average (-1.20°C to -0.51°C of average) for parts of Waikato, Taranaki, Wellington, Tasman and the West Coast. The remainder of the country experienced near average (-0.50 to +0.50°C of average) temperatures.

Rainfall was below normal (50-79 per cent of normal) or well below normal (

Sunshine in December was well above normal (>125 per cent of normal) in the north and west of the North Island as well as parts of the West Coast, Southland and Otago. Sunshine was near normal (90-109 per cent of normal) or above normal (110-125 per cent of normal) for the remainder of the country.