Sunshine hours

  • Image, Sunshine hours.

    Archived 19 October 2017

    Sunshine is important for our health and recreation, and for the environment. It is also important for our agriculture-based economy, for example, for plant growth.

    We classified Sunshine hours as a case study.

    Key findings

    Sunshine hours vary across the country each year.

    • On average from 1972 to 2013:
      • parts of the Northland, Bay of Plenty, Gisborne, Hawke’s Bay, Nelson, Tasman, and Malborough regions had high annual sunshine hours (more than 2,250)

      • the three main population centres of Auckland, Christchurch, and Wellington had relatively high annual sunshine hours (2,001–2,250)

      • parts of the Southland region and the Southern Alps had low annual sunshine hours (fewer than 1,500).

    • In terms of annual sunshine hours:
      • 2013 is an example of a year with relatively high sunshine hours – most of New Zealand had more than 2,000

      • 1992 is an example of a year with relatively low sunshine hours – most of New Zealand had fewer than 1,900.

    • In terms of percentage of normal sunshine hours:
      • in 2013, most regions had near average (90–100 percent of normal) or above average sunshine hours (100–110 percent of normal)

      • in 1992, most regions had below their normal sunshine hours (60–90 percent of normal).

    Figure 1

    Map, Average annual sunshine hours, 1972–2013.

    Figure 2

    Annual sunshine hours, 1972–2013 – interactive map

    Figure 3

    Percentage of normal sunshine hours, 1972–2013 – interactive map

    Definition and methodology

    Sunshine hours is an indicator of the annual number of sunshine hours and the percentage of normal (average) sunshine hours in New Zealand. We calculated the normal from the mean values from 1981 to 2010.

    NIWA mapped mean annual sunshine hours from the virtual climate station network data of its National Climate Database, for the period 1981–2013. It generated the percentage of normal by comparing the annual average to the long-term mean for 1981–2010 (NIWA, nd). We used this data to create our maps.

    Data is for a calendar year (January–December).

    Take care when you compare maps of different years. Days might be missing from some observations used to build the sunshine hours geographic information systems (GIS) dataset. As a result, data may have been interpolated to complete the dataset. The interpolation accuracy is lowest in areas of high elevation, where there are fewer climate stations and the complex terrain affects accuracy. Also, climate stations open and close over time, which affects the accuracy of the data.

    Data quality

    We classified Sunshine hours as a case study.

    Relevance

     This case study is a direct measure of the ‘Sunshine hours and solar intensity’ topic.

    Accuracy

     The accuracy of the data source is of high quality.

    See Data quality information for more detail.

    References

    NIWA (nd). Virtual climate station data and products. Accessed 3 June 2015 from www.niwa.co.nz.

     

    Published 21 October 2015

Top
  • Share this page
  • Share this page to Facebook
  • Share this page to Twitter
  • Share this page to Google+