Does warmer weather stop the outbreak of COVID-19?
Anika H. Ahmed, MD
From the evidence so far, the COVID-19 virus can be transmitted in all climates, including areas with hot and humid weather. Research indicates that in order to kill the Covid-19 Coronavirus, heat virus containing objects for 3 minutes at temperatures above 75°C (160°F), 5 minutes for temperatures above 65°C (149°F) and 20 minutes for temperatures above 60°C (140°F). This indicates that hot weather with temperatures above 75°C (160°F can shorten the life span of the virus but it can still be transmitted. Scientists remain busy studying the correlation of COVID-19 and temperatures. These studies have indicated that as the air gets hotter and more humid, the Coronavirus remains suspended in droplets for much lesser time and drops to the ground. The warmer summer temperatures carry more moisture, and the Coronavirus does not travel far in humidity. This reduces the virus range and also concentration available for cross infection from person to person, in cases when people come into close contact with each other. Rising temperatures also bring more people outdoors and into open spaces, which is by far a less conducive environment for Coronavirus to thrive and spread.
COVID-19 started in winter of 2019 in China and as the weather got warmer many hoped that it will slowly taper off, with the temperatures soaring upward. However, the last summer season indicated that the Coronavirus continued to spread, especially in communities not following the prevention protocols. The fact that influenza and colds occur mostly in winter is mainly because the air is drier, and the virus lasts longer in droplets suspended in air. The Coronavirus has spared no part of the globe and cases have sprouted up on hot and humid islands like Singapore, Indonesia, and Malaysia.
The ongoing research and case studies conducted so far indicate that the spread of COVID-19 is dependent mainly on the population density, lifestyle of the people with or without social distancing measures, and availability of public health tools like testing and contact tracing. These factors have a deeper impact by far than does the weather.
Increasingly, research indicates that warmer temperatures may not be able to stop the pandemic, but they may be able to slow down the sprout of new cases. The effects of low or high temperatures may explain why certain areas of the tropics have not been hit quite as hard as compared to the temperate regions of the globe. Some scientists have started incorporating temperatures in their study models for COVID-19, and have concluded so far that yes, there is a correlation, roughly about 2%-3% reduction in transmission for every degree Celsius increase in temperature. Relative atmospheric pressure and humidity certainly added to this effect It is not a big difference but certainly a relevant factor.
However, there is not enough clinical data available to establish high temperatures as a key to controlling the pandemic of COVID-19. Even as the temperatures continue to fluctuate between high and low (a frequent pattern seen now due to climate change) everyone must be cautious and continue to practice social distancing of at least 6 feet and wearing masks, especially in closed spaces and around infective COVID-19 positive individuals. Warmer weather by itself cannot end the pandemic, even though it can help in reducing the transmission of the Coronavirus and thus control the fatal pandemic somewhat. Regardless of climate, adopt protective measures if you live in, or travel to an area reporting COVID-19, especially in areas with new variants.