Before revision: 0.0096]) in the U.S. ), and one percent relative humidity rise reduces R value by 0.0078 ( 0.0076 (95\% CI [-0.0108,-0.0045]) in China and  0.0080 (95\% CI [-0.0150,-0.0010]) in the U.S. ). If assuming a 30 degree and 25 percent increase in temperature and relative humidity from winter to summer in the northern hemisphere, we expect the R values to decline about 0.89 (0.69 by temperatureand 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 .
After revision: 0.0096]) in the U.S. ), and one percent relative humidity rise reduces R value by 0.0078 ( 0.0076 (95\% CI [-0.0108,-0.0045]) in China and 0.0080 (95\% CI [-0.0150,-0.0010]) in the U.S. Therefore, the potential impact of temperature/relative humidity on the effective reproductive number alone is not strong enough to stop the pandemic .