Before revision:  It indicates that the arrival of summer and rainy season ] ] ] ] in the northern hemisphere can effectively reduce the transmission of the COVID-19. We also developed a website to provide R of major cities around the world according to their daily temperature and relative humidity: URL
After revision:  It indicates that the arrival of summer and rainy season ] ] ] ] in the northern hemisphere , we expect the R values to decline about 0.89 (0.69 by temperature and 0.20 by humidity). Given the notion that the non-intervened R values are around 2.5 to 3, only weather factors cannot make the R values below their critical condition of R<1, under which the epidemic diminishes gradually. Therefore, public health intervention such as social distancing is crucial to block the transmission of COVID-19 even in summer.