A free program for Android, by Spark 64.

UVLens is an application that will allow you to know the ultraviolet radiation level, the time that it will rise, and the time that you need to wear sunscreen. It is very useful for people that live in areas where the UV radiation is intense, as it will help them to know when it is safe to be outside.

To know the UV radiation level, you need to install the UVLens application to your mobile device. The first step is to enter your location, so that the application can detect and then measure the UV radiation level for you. Next, you need to choose the time of your daily exposure to the sun. The UV application will then tell you the time that you need to wear sunscreen and when you can be outside.