The Global UVB Solar Index was developed as a tool to inform the public about the intensity of solar ultraviolet (UVB) radiation in different regions of the world. In this context, exploratory research was conducted in San Juan del Sur Bay, Nicaragua, during 2023, with the aim of evaluating UVB radiation levels and their relationship with environmental and astronomical variables from a physical-medical perspective focused on public health. Measurements were taken at different times of the day, with emphasis on the period between 10:00 a.m. and 2:00 p.m., when solar radiation is most intense. Pearson's correlation coefficient was applied for the analysis, finding a strong positive correlation between UVB radiation and solar altitude, and a negative correlation with cloudiness. Although no direct relationship with diseases such as skin cancer or cataracts was identified, individual protection and genetic factors are recognized as influencing their onset. The results allowed for the identification of time zones and areas of greatest risk, and preventive measures were proposed, such as avoiding direct sun exposure during peak hours, using sunscreen, appropriate clothing, and UV-filtering lenses. This study contributes useful evidence for the design of public health strategies and the promotion of safer and more sustainable tourism in Nicaragua, especially in coastal areas with high sun exposure.