New Zealand has just had its hottest summer on record.
The average temperature was 18.8degC, which was 2.1degC above the 1981-2010 average, NIWA says.
The figure beat the historical record previously held by the 1934-35 summer of 18.5degC.
NIWA says the 2017-18 season was characterised by mean sea level pressures that were higher than normal to the east and southeast of New Zealand, and lower than normal over and to the west of the country.
This pattern delivered more frequent warm northerly and north-easterly winds than normal, consistent with La Nina conditions.
The summer got off to a hot start with nearly the entire country observing well-above average warmth during December, which was the second warmest December on record.
January 2018 was the hottest month on record for New Zealand with a mean of 20.3degC.
February was characterised by the passage of ex-tropical cyclones Fehi and Gita, which brought significant amounts of rainfall to parts of the country.
- Alexandra had the highest temperature of 38.7degC on January 30
- Mt Cook Airport and Tekapo had the lowest temperature of 0.2degC on December 20
- Upper Takaka had the highest one-day rainfall of 297mm on January 17
- Akitio had the strongest wind gust of 165km/h on December 19
Of the main centres:
- Auckland was warmest
- Hamilton was wettest and least sunny
- Wellington was sunniest
- Dunedin was coolest and driest