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UVI smartphone apps

Several apps that provide forecasts of the UV index (UVI) are available for smartphones. These apps use NIWA data but are not NIWA products.

Download a detailed explanation of the calculation of UVI for Smartphone apps.


UVNZ is an update of the older uv2Day app (see below). The app:

  • Tells you the current UVI (with or without cloud effects)
  • Shows how the UVI will change over the day (so you can plan your day to minimise your risk of skin damage)
  • Shows how long you can be exposed to sunlight at any time of day without visible signs of skin damage. The times are surprisingly short in summer!
  • Invites you to enter your skin type and can provide tailored behavioural advice
  • Currently provides UVI forecasts for the New Zealand region only – and is the preferred app for this region. Outside of New Zealand we recommend that you continue to use the GlobalUV app (or the uv2Day app for the wider South Pacific region) – see below for more about these.

UVNZ is freely available for iPhone and Android. It uses new data feeds from NIWA is supported by the Cancer Society of New Zealand.



NIWA data is also used in the uv2Day app. This app:

  • Provides forecasts of the UV Index (UVI) with and without cloud effects throughout the day for locations within the New Zealand, Australia and South Pacific region, including Antarctica. 
  • Can forecast the UVI for your nearest location or you can select a location.
  • Includes behavioural messages and is useful for planning activities to optimise sun exposure throughout the year, as well as for understanding what the UVI means.

UV2Day is freely available for iPhone and Android.



GlobalUV provides estimates of the current UVI and how it is expected to vary throughout the day at any location throughout the globe. The app:

  • Provides behavioural advice on how long you can remain in sunlight before damage occurs for your selected skin type.
  • Helps you plan your day to optimise your UV exposure.
  • Is an extension of the uv2Day app (which applies only to the Pacific region, where aerosol extinctions are small). Unlike uv2Day, GlobalUV uses forecasts of ozone and cloud effects to calculate UVI on the fly. At a small cost in speed, there is a huge benefit in versatility.
  • GlobalUV also provides information about position, altitude, sun elevation angle, ozone amounts, aerosol extinctions, and effects of clouds and surface reflectance (e.g., due to snow cover) and shows the current global pattern of UVI.  

GlobalUV is freely available for android and iPhones. The android version can also display clear-sky UVI values for other seasons at any location. 


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