Is high relative humidity associated with childhood hand, foot, and mouth disease in rural and urban areas?

•The humidity effect on childhood HFMD by a distributed lag non-linear analysis in rural and urban areas was first detected.•Their study explored the effects of humidity on childhood HFMD at a daily scale using a time series analysis.•This is the first paper to explore the relationship between humidity and HFMD by using the data of the peak period of incidence.