The outbreak of coronavirus disease in 2019 has become a serious threat to human health. Whether meteorological conditions could influence the transmission and virulence of COVID-19 remains controversial. In this study, we systematically reviewed the impact of temperature and humidity on the replication, morbidity, and mortality of COVID-19. We also discussed the main factors underlying the inconsistency across studies. Pubmed, Web of Science, Embase, and Scopus were used to identify papers published up to 7 December 2020. We initially identified 3515 papers, and 28 articles met the inclusion criteria after screening. Most studies showed high temperature and high humidity can partly reduce the reproduction, morbidity, and mortality of COVID-19. But the rest papers failed to identify a significant association. The discrepant results may be related to the difference in the climate context, study design, exposure assessment, policy intervention, socioeconomic status, and public health service.
Keywords: COVID-19; humidity; meteorology; systematic review; temperature.