New Zealand Eleven Station series audit

New Zealand raw temperature fraction audit

Within the Eleven Station series of records maintained by the National Institute of Water and Atmospheric Research (NIWA) in New Zealand, 16.2% of all raw temperatures were logged as a whole .0 Fahrenheit integer before Celsius metrication on 1 July 1971.

This compares with 25.5% in New Zealand's Seven Station series, 30% in Australia's ACORN-SAT dataset and 31.04% in Australia's HQ dataset series of all temperatures recorded as .0 Fahrenheit before Celsius metrication in September 1972. The correct proportion should be around 10%.

Combined, New Zealand's Eleven and Seven Station series totalled 22% of Fahrenheit temperatures recorded before July 1971 as .0F.

Eleven Station series

The Eleven Station series estimates New Zealand's average annual temperature has increased by 1C since 1930, based on unadjusted raw data from 11 weather stations that have had no significant site changes since the 1930s.

The 22 stations that are analysed in the Eleven Station series are:

Raoul Island stations - Raoul Island 6169, Raoul Island AWS 6170

Tauranga Aero stations - Tauranga Aero 1612, Tauranga Aero AWS 1615

Hamilton, Ruakura stations - Hamilton, Ruakura 2101, Hamilton, Ruakura EWS 12616, Hamilton, Ruakura 2 EWS 26117

Gisborne Aero/AWS stations - Gisborne Aero 2807, Gisborne AWS 2810

Mt Ruapehu, Chateau stations - Mt Ruapehu, Chateau 1 2363, Mt Ruapehu, Chateau 2 2357, Mt Ruapehu, Chateau EWS 18464

Palmerston N stations - Palmerston N 3238, Palmerston North EWS 21963

Westport Aero stations - Westport Aero 3810, Westport Aero AWS 7342

Molesworth stations - Molesworth 4461, Molesworth AWS 7427

Queenstown stations - Queenstown 5446

Invercargill Aero Aero stations - Invercargill Aero 5814

Campbell Island stations - Campbell Island 6172, Campbell Island AWS 6174

Data from these different stations in 11 locations are merged by the NIWA to create an average raw temperature trend.

In total, the audited Eleven Station dataset includes 202,232 minimum and maximum Fahrenheit temperatures recorded at 22 weather stations before July 1971 and 327,750 minimum and maximum Celsius temperatures recorded at all stations from 1 July 1971 to 31 December 2011, totalling 529,982 recordings.

Fahrenheit .0 rounding before 1971

In the Fahrenheit era before July 1971, 16.2% of all temperatures recorded at the 22 New Zealand stations were logged as .0F degrees.

The combined 28.1% of temperatures recorded as .9F and .1F infers an actual .0F ratio around 30%.

$elevent station temperature fractions$

A breakdown of this data shows that 15.5% of all Fahrenheit maxima recorded before July 1971 were rounded to .0F and 16.9% of all minima were rounded to .0F. As in Australia and in New Zealand's Seven Station series, there is a greater proportion of minima recorded as .0F than maxima.

new zealand maximum temperature roundings

$new zealand minimim temperature fractions$

The proportions of total converted Celsius fractions recorded at all 22 weather stations before 1 July 1971 were:

$new zealand seven station temperature fractions$

Celsius .0 rounding after 1971

In the Celsius era from 1 July 1971 to 31 December 2011, 13.2% of all temperatures recorded at all 22 New Zealand locations within the Eleven Station dataset were recorded as .0C degrees.

$new zealand celsius fractions$

A breakdown of this data shows that 13.6% of all Celsius maxima recorded since July 1971 were rounded to .0F and 12.7% of all minima were rounded to .0F. Unlike Fahrenheit fractional distribution, this shows a slight tendency for more maxima than minima to be rounded to .0.

$new zealand maximum temperature fractions$

$new zealand minimum temperature fractions$

Six of the 22 stations have blocks of consecutive .0C and .5C recordings, all since 1 July 1971, which contribute a small amount of the high .0C proportion in the Celsius era. These consecutive blocks of rounded .0C and .5C are thought to be software problems but are not as common in New Zealand's Celsius era records as they are in Australia.

Below are the minimum and maximum percentages of whole .0 Fahrenheit recordings at each of the 22 stations before 1 July 1971:

Click station names for full audit results

Station	Minima .0F %	Maxima .0F %
Raoul Island 6169	14.1%	14.2%
Raoul Island AWS 6170	Opened after 1971	Opened after 1971
Tauranga Aero 1612	13.8%	15.2%
Hamilton, Ruakura 2101	13%	10.2%
Hamilton, Ruakura EWS 12616	Opened after 1971	Opened after 1971
Hamilton, Ruakura 2 EWS 26117	Opened after 1971	Opened after 1971
Gisborne Aero 2807	14%	14.5%
Gisborne AWS 2810	Opened after 1971	Opened after 1971
Mt Ruapehu, Chateau 1 2363	21.7%	22.9
Mt Ruapehu, Chateau 2 2357	Opened after 1971	Opened after 1971
Mt Ruapehu, Chateau EWS 18464	Opened after 1971	Opened after 1971
Palmerston N 3238	21.1%	18.1%
Palmerston North EWS 21963	Opened after 1971	Opened after 1971
Westport Aero 3810	32.7%	32.3%
Westport Aero AWS 7342	Opened after 1971	Opened after 1971
Molesworth 4461	35.5%	30.4%
Molesworth AWS 7427	Opened after 1971	Opened after 1971
Queenstown 5446	14.3%	10%
Invercargill Aero 5814	14.5%	13.4%
Campbell Island 6172	14.9%	16.3%
Campbell Island AWS 6174	Opened after 1971	Opened after 1971

The full results for this audit of Eleven Station series locations in New Zealand are within:

TableofSites-scanned-11.xls (Excel download 90kb).

Note: This audit of New Zealand weather station temperature records was possible due to the Excel programming skills of former ABS statistician Ian Hill.

Eleven Station and Seven Station series combined

When the 22 locations in the Eleven Station series are combined with the 25 locations in the Seven Station series, the 47 locations together had 22% of Fahrenheit temperatures recorded as .0F before July 1971 - see chart. Combined, all 47 stations together had 14.3% of Celsius temperatures recorded as .0C since July 1971 - see chart.

A breakdown of this data shows that 21.7% of all Fahrenheit maxima recorded before July 1971 were rounded to .0F and 22.4% of all minima were rounded to .0F.

Since July 1971, 14.6% of all Celsius maxima were rounded to .0F and 14.1% of all minima were rounded to .0F.

The 47 stations combined had 549,493 recordings of Fahrenheit temperatures before July 1971 and 616,764 recordings of Celsius temperatures after July 1971, totalling 1,166,257 recordings.

Below are audit results for each of the 22 Eleven Station locations

Raoul Island 6169 maximum temperature audit
9 March 1940 to 1 November 2011

At Raoul Island 6169 from 9 March 1940 to June 30 1971, whole .0 Fahrenheit degrees represented 14.2% of all maximum temperatures recorded.

1940-1971 represented 43.7% of the time span and had 20.2% of .0C and 27.8% of .5C maximum temperatures within the entire temperature record.

From 1971-2011, maximum temperature recordings of .0 Celsius degrees represented 21.6% of the total and .5C recordings represented 10.7% of the total of all fractions since 1971. Together, .0C and .5C represented 32.3% of all maximum temperatures recorded since metrication.

Raoul Island 6169 minimum temperature audit
9 March 1940 to 1 November 2011

Raoul Island 6169 from 9 March 1940 to June 30 1971, whole .0 Fahrenheit degrees represented 14.1% of all minimum temperatures recorded.

1940-1971 represented 43.7% of the time span and had 29% of .0C and 24.9% of .5C minimum temperatures within the entire temperature record.

From 1971-2011, minimum temperature recordings of .0 Celsius degrees represented 13.1% of the total and .5C recordings represented 12.3% of the total of all fractions since 1971. Together, .0C and .5C represented 25.4% of all minimum temperatures recorded since metrication.