UV & Ozone
This is the home for NIWA's UV and ozone research, including maps and graphs showing daily predictions and measurements for UV levels across New Zealand.
Daily Predictions and Measurements
This information is provided by NIWA free of charge and can be used only for personal use. Repackaging and on-selling in any form is prohibited.
What is the UV index?
The UV index is a standard measurement of erythemal (sun-burn causing) UV intensity that gives a more objective measure than the old “time to burn” (which cannot account for skin tone). The scale is open-ended, but a UV index of greater than 10 is extreme and a UV index of less than 3 is low. For clear skies, the UVI depends mainly on the sun elevation angle and the ozone amount, view here. The UVI also depends on cloud cover, sun-earth separation, altitude, pollution, and surface reflections (e.g., snow cover). The highest values in the world occur in the tropics at high altitudes, where the UVI can exceed 25. The geographical and seasonal variation in peak UVI for New Zealand can be viewed here. In the NZ winter, the UVI rarely exceeds 3. Because of differences in ozone, sun-earth separation and pollution, the peak UVI in NZ is approximately 40% greater than at comparable latitudes in the Northern Hemisphere.
Current UV Index at specific NZ sites
Graphs showing predicted and measured UV Index at Lauder are updated at 15 minute intervals. Unlike the UVI predictions seen on TV, these include the effects of clouds. The most recent UVI is displayed, along with a corresponding behavioural message. These messages correspond to five intensity ranges, as recommended by Sunsmart and the Cancer Society of New Zealand. We plan to make similar data from other sites available in this way at a later date but currently data are downloaded from most instruments elsewhere only once per day.
New Zealand Ozone and UV Index Maps for noon (12:00NZST, 0:00GMT)
The maps provided here are forecasts modelled on available satellite ozone data.
| Yesterday | UV Index Clear Sky | UV Index Cloudy | Ozone |
|---|---|---|---|
| Today | UV Index Clear Sky | UV Index Cloudy | Ozone |
| Tomorrow | UV Index Clear Sky | UV Index Cloudy | Ozone |
Yesterday's UV Index at specific sites in NZ and the South Pacific
Graphs showing predicted and measured UV Index at Leigh, Paraparaumu, Christchurch, Lauder, Invercargill and Rarotonga are updated daily.
UV Index Displays
NIWA has been working with the Cancer Society to develop UV Index Displays for the public that record current levels of UV. For more information please contact Richard McKenzie ( r.mckenzie@niwa.co.nz ).
UV forecasts for Specific Sites
Graphs showing UVI forecasts specific sites in New Zealand and the South Pacific region. When the UVI is low (less than 3), no protection is required and short exposures to sunlight will be beneficial for vitamin D production. At all other times some protection to avoid sunburn is recommended. The "UV Alert Period" is defined as the period when the clear sky UVI forecast is greater than 3. When the UVI is 3, damage to fair skin can occur in less than 1 hour. When the UVI is 12, damage to fair skin can occur in less than 15 minutes. For darker Polynesian skin types the safe exposure periods can be doubled
Personal UV Dosimeters
There is widespread public interest in the relationships between UV radiation and health. The effects of UV on health can be harmful – as in its effect on skin cancer rates, or beneficial – as in the case of its effect on vitamin D status. In the past, researchers have attempted to determine these relationships as functions of ambient UV radiation. However, the UV doses that humans are typically receive are less than 5% of that available UV.
Read more about personal UV dosimeters.
The UV Atlas project
The aim of the UV Atlas project is to produce maps and time series of parameters describing the UV radiation environment over New Zealand since 1960. Maps are produced for the area around New Zealand (34° to 48° S, 166° to 180° E), and time series are produced at sites where broadband radiation measurements are available.
Click for more information on the:
- outputs produced by this project,
- details on how to obtain the data,
- access to data viewing software and its documentation.
Latest All-Sky Image at Lauder, New Zealand
The all-sky image shows a hemispheric view of the sky at Lauder. These images record the cloud cover at Lauder for use in the atmospheric radiation research. The images are updated every 10 minutes and an archive image is available for each of the last 24 hours.
Daily Lauder Ozone Records
The daily ozone level at Lauder as measured by the Dobson spectrophotometer can be viewed at NOAA’s CMDL Dobson Data Graphing website
. This plot shows the current years data. From here you can also view the records for Lauder and other sites around the world since data collection began.
Range of UV Measurements
NIWA's UV Measurements project is based at Lauder, Central Otago. Several 
UV measurement programmes are maintained there as well as at other sites.
Daily Lauder UV Records
A suite of radiation sensors from the USDA (Department of Agriculture) was installed at Lauder on 20 November 2001. This gives us an added capability of measuring direct, diffuse and global radiation in both the UV and visible spectral regions, with calibrations provided from the Sun without recourse to problematic lamp calibrations. An additional benefit is that UV intensities in New Zealand can be directly compared with 30 other sites (mainly in USA). The equipment was installed by Colorado State University, the agency that maintains the network. Measurements at these sites, including Lauder, are available at the USDA UVB Radiation Monitoring Program [ uvb.nrel.colostate.edu/UVB/uvb_climate_network.html ].
Instruments at Lauder
NIWA’s atmospheric research site at Lauder is one of five primary charter sites for the International Network for the Detection of Stratospheric Change (NDSC). Initially this network was set up to investigate long-term changes in the atmosphere resulting from increases in ozone-depleting chemicals. The scope has been broadened and the measurements available now include quantities that are relevant to broader issues of climate change, such as global warming. Consequently, there is a wide range of state-of-the-art equipment at Lauder, much of which is operated with international partners, providing ongoing data on a wide range of atmospheric constituents and radiation quantities. Lauder data are also archived in the World Ozone and Ultraviolet Radiation Data Centre (WOUDC) and in the Baseline Surface Radiation Network (BSRN). NIWA UV spectrometers are available commercially.
Further UV information
Further information about UV radiation in New Zealand and its effects on the environment is available from papers presented at NIWA UV Workshops in 2002 and 2006. Pdf versions of these are available at www.niwascience.co.nz/rc/atmos/2006/papers and www.niwascience.co.nz/rc/atmos/2002/papers