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.
April 2021 had a rainfall of 45 mm.
total rainfall for the fours months January to April 2020 of 87 mm was the lowest rainfall for the January to April period since observation began in 1898. In comparison the total rainfall for the fours months January to April 2021 was 160 mm and the average rainfall for the four months January to April is 407 mm.
The graph shows the range of rainfalls from a high of 383 mm in 1911 to a low of 10 mm in 1958.
The second wettest April was 1948, when 333 mm was recorded; and the second driest was April 2010 with only 12 mm.
The long-term average rainfall for Tauranga for April is 120 mm.
Since 1898, there have been 11 April months with a rainfall of 250 mm or more.
In chronological order, the wettest April months are: 1911, 1923, 1935, 1938, 1948, 1959, 1995, 2000, 2001, 2013, and 2017.
In terms of dry April months, there have been ten months with rainfall of 30 mm or less.
In chronological order, the driest April months are: 1898, 1910, 1913, 1919, 1958, 1979, 1984, 2005, 2010 and 2020.
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