Environmental Reporting, Ministry for the Environment and Statistics New Zealand
Sunshine is essential for our mental and physical well-being and plant growth. It is also important for tourism and recreation. More information on this dataset and how it relates to our environmental reporting indicators and topics can be found in the attached data quality pdf.
Method: NIWA extracted data for sunshine hours from the Climate Database for all stations with data (approximately 90 stations across the country) for the particular year. NIWA then interpolated the data to create a regular 500m resolution grid of average annual sunshine hours for each year from 1972 to 2016. Missing data were infilled using Virtual Climate Station Network data (NIWA, nd). Be cautious when interpreting interpolated data because interpolation accuracy is affected by stations opening or closing over time, station density, and terrain complexity. The type of instrument used for recording sunshine hours may change over time which could also influence results. Data are for a calendar year (January–December). NIWA calculated percent of normal sunshine hours by comparing interpolations of the annual average for each year to the long-term average for 1981–2010. The most recent three-year average (2014–16) percent of normal annual sunshine hours was created by averaging the three individual year interpolations.