Ultraviolet radiation is responsible for premature aging, melanomas, carcinomas and a large number of cases of skin cancer, despite the fact that it is the easiest risk factor to prevent in people. There are sources such as web and mobile applications and even industrial instruments that claim to measure the UV radiation index (UVI). In this work, four experiments were conducted to evaluate the relationship of the UV radiation index (UVI) with time and climatic variables such as humidity, temperature and sky condition. We found industrial instrument indicates lower radiation values, since it has a sensor that is affected by various climatic factors, while the applications that use the Global Positioning System (GPS) indicate high values. However, it was also determined that the margin of error of these is tolerable for taking preventive measures. We contribute with a collected data set of UVI and weather condition in Peru.