Influenza seasonality is influenced by environmental and ecological conditions as well as evolutionary processes shaping the transmission potential of airborne Influenza A virus (IAV) particles and subsequent infectious disease. Considering fluctuating environmental conditions with absolute humidity as a key driver, we analyzed environmental effects on the infection dynamic in Germany during the influenza seasons between 2010 and 2018. Despite the fact that Germany is a comparably homogenous country with regard to socio-economical, and environmental properties, influenza seasons differed significantly between individual German counties and cities, with a clear gradient in incidence and intensity between the Southeast and Northwest. Thus, the transmission of IAV influenced by slight differences in the predominant weather conditions throughout Germany, emphasizing the importance of air temperature and absolute humidity for airborne flu virus transmission.
