NIWA's 'seven-station' series has been re-analysed, and independently peer-reviewed, and the result confirms a NZ-wide warming trend. Here we provide links to extensive documentation for each of the 'seven stations'.

For each location, temperature records from a number of local sites have been merged together to form a long time series. When merging different temperature records like this, it is necessary to adjust for climatic differences from place-to-place, or even changes in exposure or instrumentation at the same site. If no adjustments are made, significant biases could be introduced.

Documentation of adjustments at each location

NIWA scientists have prepared extensive documentation describing in detail how they developed composite temperature series for each of the seven locations:

The changes in average temperature (anomalies) for each site are then combined to calculate a temperature trend for New Zealand.