Abstract: International Journal of Environmental Research and Public Health Article Correlation between UV Index, Temperature and Humidity with Respect to Incidence and Severity of COVID 19 in Spain Juan Blas Pérez-Gilaberte 1 , Natalia Martín-Iranzo 2 , José Aguilera 3, * , Manuel Almenara-Blasco 4 , María Victoria de Gálvez 3 and Yolanda Gilaberte 4 1 2 3 4 * Citation: Pérez-Gilaberte, J.B.; Martín-Iranzo, N.; Aguilera, J.; Almenara-Blasco, M.; de Gálvez, M.V.; Department of Internal Medicine, Miguel Servet University Hospital, IIS Aragon, 50009 Zaragoza, Spain Medical School, University of Zaragoza, 50009 Zaragoza, Spain Photobiological Dermatology Laboratory Medical Research Center, Department of Dermatology and Medicine, School of Medicine, Campus Universitario de Teatinos S/N, 29071 Málaga, Spain Department of Dermatology, Miguel Servet University Hospital, IIS Aragon, 50009 Zaragoza, Spain Correspondence: jaguilera@uma.es; Tel.: +34-(95)-2137540 Abstract: Background: Various studies support the inverse correlation between solar exposure and Coronavirus SARS-CoV-2 infection. In Spain, from the Canary Islands to the northern part of the country, the global incidence of COVID-19 is different depending on latitude, which could be related to different meteorological conditions such as temperature, humidity, and ultraviolet index (UVI). The objective of the present work was to analyze the association between UVI, other relevant environmental factors such as temperature and humidity, and the incidence, severity, and mortality of COVID-19 at different latitudes in Spain. Methods: An observational prospective study was conducted, recording the numbers of new cases, hospitalizations, patients in critical units, mortality rates, and annual variations related to UVI, temperature, and humidity in five different provinces of Spain from January 2020 to February 2021. Results: Statistically significant inverse correlations (Spearman coefficients) were observed between UVI, temperature, annual changes, and the incidence of COVID-19 cases at almost all latitudes. Conclusion: Higher ultraviolet radiation levels and mean temperatures could contribute to reducing COVID-19 incidence, hospitalizations, and mortality. Keywords: COVID-19 incidence; hospitalizations; mortality; ultraviolet radiation; temperature Gilaberte, Y. Correlation between UV Index, Temperature and Humidity with Respect to Incidence and Severity of COVID 19 in Spain. Int. J. Environ. Res. Public Health 2023, 20, 1973. https://doi.org/10.3390/ijerph 20031973 Academic Editor: Paul B. Tchounwou Received: 20 December 2022 Revised: 12 January 2023 Accepted: 15 January 2023 Published: 20 January 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).