There are many lines of evidence showing that NZ has warmed during the past century.
These include the "seven station" temperature series, the "eleven station" temperature series, and information from ship measurements of sea-surface temperatures and marine night-time air temperatures over the oceans around NZ.
‘Seven-station’ series
NIWA's 'seven-station' temperature series uses temperature measurements from seven 'climate stations'. The locations were chosen because they provide a representative geographical spread across NZ and have reliable records dating back at least to the early 1900s. The linear trend in the annual average temperature over the period 1909 to 2018 is a warming of 1.09ºC (or a rate of 1.00ºC per 100 years).
'Eleven-station' series
This series comprises a set of eleven stations spanning New Zealand where there have been no significant site moves for many decades. The data used in this series are raw (unadjusted) – no adjustments are required because the measuring sites have not moved significantly. There is a warming trend over the 77-year period 1931-2008 of close to 1 ºC. Note that the 11-station series ends in 2009 and is not being updated.
Sign up for free access to NIWA’s raw climate data
NIWA is a world leader in providing raw climate data free over the web.
Climate station data is available in the NIWA DataHub.
Review
In 2010 NIWA was asked to verify its work through various review processes. Learn more about this process
Related links
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'Seven-station' series temperature data
Research ProjectNIWA's long-running 'seven-station' series shows NZ's average annual temperature has increased by about 1 °C over the past 100 years. -
'Eleven-station' series temperature data
Research ProjectTemperature trends from 1930s to present day -
Review
NIWA's work on long-term temperature trends has been subject to various review processes.