The National Institute of Water and Atmospheric Research (NIWA) is expecting drier than normal and above average temperatures between August and October.
In its seasonal climate outlook, released today, NIWA also said ocean and atmosphere conditions were trending to La Nina.
"The climate system is showing similarities to this time last year, which featured La Niña development during spring," the weather agency said.
"Temperatures are most likely to be above average in all regions of the country.
"More northwesterly air flows will likely cause spells of unseasonably warm temperatures in the north and east of both islands in particular."
Higher than normal air pressure, especially to the north and east of the country, is expected to bring spells of drier than normal conditions to many regions through the three month period.
However, while it'll be dry for many regions, NIWA also said rainfall is about equally likely to be near normal or above normal in the west of the South Island and most likely to be near normal in the west of the North Island.
NIWA said it's Seasonal Climate Outlook, put together by its climate scientists, was not a forecast, though, as it is not possible to forecast weather months out.
The agency instead indicates the likelihood of climate conditions being at, above, or below average for the season as a whole.
However, it also stated its forecast confidence for temperatures was medium to high and its forecast confidence for rainfall was medium.