In his peer-reviewed 1980 paper Apparent Trends of Mean Temperature in New Zealand Since 1930, JWD Hessell found that exposures of most New Zealand weather stations have been affected by changes in shelter, screenage and/or urbanisation, all of which tend to increase the observed mean temperature. A systematic analysis reveals that no important change in annual mean temperature since 1930 has been found at those stations where the above factors are negligible.