Weather Eye with John Maunder

Temperatures have been recorded in the Tauranga area at several sites over the last 100 years including the current Tauranga Airport site from June 1990.

It is very common for areas such as Tauranga to have had different observation sites over the years and the readings from the earlier sites have been adjusted to the present site using "standard climatologically procedures".

It is considered that the temperature series described here is a fair and true record of what the temperature would have been if the current observation site (Tauranga Airport) had been used throughout the period.

It is important to note, that in considering 'climate change”, the methodology used in computing an ‘official' set of climate observations is very important as otherwise erroneous conclusions may be drawn.

Traditionally, temperature observations have been recorded with a set of maximum and minimum temperature thermometers. These record the daily maximum temperature (usually recorded in mid-afternoon), and daily minimum temperature (usually recorded just before dawn).

This analysis of temperatures for Tauranga are those for the average daily maximum temperatures. Later analyses will be for the average daily minimum temperatures.

The graph shows details of the average daily maximum temperatures (called simply "afternoon" from now on), for Tauranga for April from 1913-2012. Note that April 1947 and 1964 are not included because of incomplete data.

The long-term average afternoon temperature in April for Tauranga for is 20 degrees C, ranging from the "cool" April months of 1925 with an average afternoon temperature of 18.2 degrees C , and 1923 with an average afternoon temperature of 18.3 degrees C, to the "warm" April months of 1938 (22.5 degrees C), and 1916 (22.4 degrees C).

The graph of the average afternoon temperatures for April shows generally "normal" variations from April to April with 1920's and the last 15 Aprils being a little "warmer" than other April months. From 1913 to 2012, there have been 12 April months with an average afternoon temperature of 21degrees or more, and eight April months with an average afternoon temperature of less than 19degrees.

The value for April 2013 was 21.5 degrees, the third warmest on record.

The 12 "warmest" April months (in terms of afternoon temperatures) on record, in chronological order, are 1916, 1924,1928, 1935,1938,1948,1955, 1956,1978, 1981, 2012, and 2013. In contrast, the 8 "coolest" April months (in terms of afternoon temperatures) on record, in chronological order, are 1923,1925,1940,1941,1949,1980,1991, and 1992.

For further information Google 'Dr John Maunder” or log onto https://sites.google.com/site/climatediceandthebutterfly/