Determining Role of Air Temperature in Predicting and Controlling COVID-19 Risk Levels Anywhere Anytime Using Multiple Modelling Analyses

COVID-19 is a pandemic with no cure. There is an urgent need for low-cost interventions. Macroclimate work through microclimate. In many situations, man-made microclimate, such as air conditioning, may override the effect of natural macroclimate in determining the pathogenicity of SARS-CoV-2. This study aimed to determine if there is a ‘safe’ temperature that is comfortable to human beings while significantly inhibitory for SARS-CoV-2 pathogenicity. Data on monthly new deaths or new cases per million population (MDPM or MCPM) and monthly cumulated days with more cases than the previous day (DI) from March 2 to June 15, 2020 were collected from all 118 countries with population over five million. Monthly average AT negatively correlated with the transmission parameters. A significant decrease in transmission was observed when AT reached above 20 ºC. Monthly average (not average high) AT of countries with MDPM <2, MCPM<10, or DI<=7 was found to be between 24.54 and 25.90 ºC (25.00 ºC on average) with average standard error of 4.97. Thus, average AT 25 ºC were considered as high, medium, and low risk AT. Furthermore, MDPM in countries with AT 25 ºC in March, April, May, and June 1-15, respectively. MDPM high-risk rates in countries with AT >25 ºC were 0, 6.25, 14.55, and 9.84%, and the low-risk rates were 100, 83.33, 52.73, and 81.97%, respectively. In countries with AT <20 ºC, the trends were opposite. Setting indoor temperature to 25 ºC could decrease the need of social distancing for containing SARS-CoV-2 transmission. Cooling indoor temperature too low may be a reason of COVID-19 outbreak in some high AT countries. Authorities and the general population can evaluate COVID-19 risk level and manipulate microclimate to reduce the risk anywhere anytime based on local day average AT.