2018 hottest summer on record

The national average temperature for New Zealand in 2018 made it the second warmest year on record, NIWA has announced.

Last year’s average temperature was equal to that of 1998 and second only to 2016, which still holds the record for the highest temperature.

That meant four of the past six years were among New Zealand’s warmest.

However, there were several record-breaking moments. January kicked off the year with the hottest-since-records-began month that later contributed to the hottest summer.

Principal scientist Chris Brandolino gave the details at the Annual Climate Summary announcement in Auckland yesterday.

The year 2018 was part of an

‘‘alarming’’ warmer trend, he said.

Extreme weather events, while already common, are also likely to increase as average temperatures continue to increase.

‘‘A changing climate is creating a long-term tail wind for higher temperatures,’’ Brandolino said.

‘‘January was [the] warmest month, of any year on record,’’ he said.

‘‘Six months of the year saw temperatures above average, with no months [with] below average temperatures.’’

The mean temperature of 2018 was 13.41 degrees, eight degrees above the long-term average. Individual climate stations experienced record or nearing-record average temperatures.

The record warmth can be attributed to three factors: Rising ocean temperature, air flow and an increase in greenhouse gases.

A ‘‘marine heatwave’’ was used to describe the sea surface temperatures, which were above average beginning in November

2017 and persisting until February

2018.

Ocean temperatures affect air temperature, which was a big contributor to the warm year also.

Rain events was described as ‘‘lumpy’’ switching from wet, to dry, to wet again throughout the year.

However, rainfall was above normal levels across much of the east and upper South Island, as well as in parts of Wellington, Wairarapa, Bay of Plenty, northern Waikato and Auckland.

The sunniest place in New Zealand was the wider Nelson region.

‘‘A changing climate is creating a long-term tail wind for higher temperatures.’’ Chris Brandolino, NIWA principal scientist