'Eleven-station' series temperature data

Temperature trends from 1930s to present day

New Zealand temperature trends from a set of eleven climate stations with no significant site changes since the 1930s

What is the eleven-station series?

We have identified from the NIWA climate archive a set of eleven stations spanning New Zealand in which there has been no significant site moves for many decades. For six of these stations these records go back to at least the 1930s.

The sites are Raoul Island, Tauranga Airport, Ruakura (Hamilton), Gisborne Airport, Chateau Tongariro, Palmerston North DSIR/AgResearch, Westport Airport, Molesworth, Queenstown, Invercargill Airport and Campbell Island.

The warming trend over the 77 year period of this series is close to 1°C

We have analysed raw data from these sites directly, making no adjustments to the numbers from the NIWA climate database. Taking all sites together and averaging the annual mean temperatures anomalies (difference from 1961–90 mean at each site) results in Figure 1 below.


Figure 1: Temperature departures from the 1961–90 normal, averaged over the eleven sites listed in Table 1. For years where not all sites are available, the average is over those that do have records.

Note that not all stations have annual mean temperature values for all years in 1931–2008. It is common practice to in-fill isolated missing months, but we have deliberately not in-filled missing data here to keep this analysis as non-contentious as possible. For each year, the available station values have been averaged. In the title of the Figure, the “p-value” comes from a statistical test, and indicates the probability that the indicated trend could have arisen by chance.

If the two outlying Island records (Raoul and Campbell Islands) are left out, and the anomalies for the remaining nine records averaged, the result is as shown in Figure 2. In either case, the trend over the 77 year period is close to 1°C.


Figure 2: Temperature departures from the 1961–90 normal, averaged over the nine sites listed in Table 1 that are located on the main islands of New Zealand (i.e., all but Raoul and Campbell Islands). For years where not all sites are available, the average is over those that do have records.

This analysis was completed by:

  • Dr Jim Salinger, Honorary Research Fellow, School of Environment, University of Auckland
  • Dr James Renwick, Principal Scientist, Climate, NIWA Wellington

Detail of the eleven-station series 

Below is a table of station names, and the associated network and agent numbers that make up the record for each site.

A link to a spreadsheet of the data (annual anomalies) for this series is at the bottom of this webpage.  

Note that while these sites have had no significant moves since the 1930s, their records may be stored in the climate database under more than one network or agent number. This is because the database archiving procedures take account of such things as a change from a manual recording system to an automated recording system. Also, some sites have records going back before 1930, but it’s the period from 1931 where all of these sites are unaffected by significant site changes.

Table 1: List of stations with long-term records where no significant site changes have occurred.

Station nameNetwork numbersAgent numbersPeriodRemarks
Raoul IsJ99700 J997016169 6170Apr 1940 – Oct 1998 Dec 1991 – present Automation of site
Tauranga AeroB76621 B766241612 1615Feb 1913 – Feb 1989 Jun 1990 – present Automation of site
Hamilton, RuakuraC75731 C75733 C757342101 12616 26117Nov 1906 – Feb 1997 Nov 1996 – Feb 2007 Dec 2005 – present Automation of site Small site shift
Gisborne Aero/AWSD87692 D876952807 2810Apr 1937 – Feb 1993 Jan 1990 – present Automation of site
Mt Ruapehu, ChateauC95251 C95152 C951532363 2357 18464Jan 1930 – Feb 1983 Mar 1981 – Oct 2000 Oct 2000 – present Small site shift Automation of site
Palmerston NE05363 E0536D3238 21963Jan 1928 – May 2001 Apr 2001 – present Automation of site
Westport AeroF11752 F117543810 7342Mar 1937 – Oct 1991 Nov 1991 – present Automation of site
MolesworthG23021 G230224461 7427Mar 1944 – Oct 1992 May 1992 – Jul 1994 Automation of site
QueenstownI580615446Nov 1929 – present
Invercargill AeroI684335814Jun 1948 – present
Campbell IsK94400 K944026172 6174Jul 1941 – Aug 1995 Dec 1991 – present Automation of site

Download the data here 

The data for these sites reside on the publicly-accessible national climate database operated by NIWA - CliFlo. For even easier access, we have posted an excel spreadsheet of the data. Note that this data set is no longer being updated.

See an explanation of how "missing data" are dealt with for this temperature series

Data may be missing for a variety of reasons, for example when an instrument malfunctions or a person fails to record the measurements or a measuring site closes.

  • (no image provided)

    Technical note on the treatment of missing data in the 11-station series

    In climate science, there are a number of accepted methods to account for missing data in temperature series. This note explains in technical terms what we did for the 11-station series.