In absence of empirical research data, there has been considerable speculative hypothesis on the relationship between climatic factors (such as temperature and humidity) and the incidence of COVID-19.
A new study analyzed the data from 310 regions across 116 countries that reported confirmed cases of COVID-19 by March 12, 2020, and found that temperature, humidity, and wind speed were inversely associated with the incidence rate of COVID-19 after adjusting for the regional and temporal trend in the incidence of COVID-19, columnar density of ozone, precipitation probability, sea-level, air-pressure, and length of daytime.
Overall, the incidence of COVID-19 increased by 11% per day after adjusting for all the variables listed above (dew point and cloud cover were initially considered, but later excluded due to multicollinearity). In the adjusted model, daily maximum temperature, relative humidity, and wind speed were associated with a lower incidence of COVID-19. There was an inverse association between COVID-19 incidence and 14-day lagged UV index (but not with the concurrent or the 7-day lagged data).
In summary, authors found that an inverse relationship between temperature (and humidity) and the incidence of COVID-19 may suggest a cold and dry environment more favourable condition for virus survival, as was proposed for other coronavirus such as SARS-CoV and MERS-CoV. Besides, an inverse association with wind speed may indicate a shorter suspending time in the air due to dilution and removal of COVID-19. Moreover, an inverse association with a higher UV index would suggest viral destruction at higher temperature, but the association did not hold with the concurrent or 7-day UV index.
Link to the paper: https://doi.org/10.1101/2020.03.27.20045658
Editorial Disclaimer: information published during the 2020 COVID-19 pandemic may be updated frequently to reflect the dynamic nature of current understanding.