NZ forecast for warmer than usual summer

Summer's on the way and this year, the heat is ramping up.

A preliminary forecast shows above-average temperatures for most of the country over summer, NIWA forecaster Chris Brandolino told the AM Show.

"The reason we have high confidence it's going to be warmer than average temperatures, [is] the ocean temperatures are higher than average around New Zealand, and north-easterly winds.

"Will there be cold snaps? Of course there will be.

"Rainfall [is] a bit more mixed. The northern and eastern part of the North Island we think that rainfall will likely be near normal or above normal so Tauranga up to Northland.

"For the west of the South Island we think that rain will be near normal or below normal."

The South Island will be on watch after October came in as one of the driest months on record.

Queenstown, Cromwell and Wanaka all received less than 6mm of rainfall, the second lowest for each in the past six decades at least.

For the North Island, this summer could bring more humid days than usual.

The official summer outlook will be released in one month.