High Temperature and High Humidity Reduce the Transmission of COVID-19

Abstract

This paper investigates how air temperature and humidity influence the transmission of COVID-19. After estimating the serial interval of COVID-19 from 105 pairs of the virus carrier and the infected, we calculate the daily effective reproductive number, R, for each of all 100 Chinese cities with more than 40 cases. Using the daily R values from January 21 to 23, 2020 as proxies of non-intervened transmission intensity, we find, under a linear regression framework for 100 Chinese cities, high temperature and high relative humidity significantly reduce the transmission of COVID-19, respectively, even after controlling for population density and GDP per capita of cities. One degree Celsius increase in temperature and one percent increase in relative humidity lower R by 0.0383 and 0.0224, respectively. This result is consistent with the fact that the high temperature and high humidity significantly reduce the transmission of influenza. It indicates that the arrival of summer and rainy season in the northern hemisphere can effectively reduce the transmission of the COVID-19.

Funding: This work was supported by the National Key R&D Program of China (2019YFB2102100 to Jingyuan Wang) and the National Natural Science Foundation of China (Grant No. 61572059 and 71531001 to Jingyuan Wang and U1811463 to Weifeng Lv).

Declaration of Interest: There is no competing interest declaration for all authors.