with John Maunder
Monthly rainfalls for Tauranga have been recorded at several recording sites during the last 122 years.
From January 1898 to December 1904, the observation site was described as the Tauranga Harbour, from November 1904 to April 1907 the site was described as simply ‘Tauranga'.From January 1910 to December 1923 the site was Waikareao, in Otumoetai; from January 1924 to September 1940 the site was at 148 Waihi Rd, in Judea; from October 1940 to January 1941 the site was at Te Puna; and from February 1941 to now, the site is Tauranga Airport.
The methodology use in adjusting the older sites to the current observing site is published in the ‘NZ Meteorological Service Miscellaneous Publication' No 180 in 1984.
It is considered that the homogeneous rainfall series described here is a fair and true record of what the rainfall would have been if the current observation site (Tauranga Airport) had been used since 1898.
This should be coupled with the understanding that although standard accepted methodologies have been used, any adjustments are only estimates of what would have occurred if the location of the rainfall records had always been in the same place with the same surroundings and the same or similar recording gauge.
In terms of climate change (such as is it getting wetter or drier, or warmer or colder), the methodology used in computing an ‘official’ set of climate observations is very important, as otherwise erroneous conclusions may be drawn.
The graph shows the range of rainfalls from an extreme high of 381 mm in 1925 to a low of 19 mm in 1906.
The rainfall in June 2020 was 262 mm, the fourth wettest June in 122 years of observations.
Since 1898, there have been 18 June months with a rainfall of 200 mm or more, and 11 June months with rainfalls of 50 mm or less.
In chronological order the wettest 18 June months are: 1915, 1917, 1920, 1925, 1930, 1935, 1939, 1943, 1946, 1961, 1968, 1971, 1981, 1985, 1997, 2010, 2014 and 2020.
By contrast the driest June months in chronological order are: 1906, 1913, 1914, 1933, 1942, 1958, 1959, 1967, 2001, 2012, and 2015.
For further information on range of climate matters see Google: climatediceandthebutterfly