A new study by US researchers indicates that summer weather slows down the spread of the coronavirus, but does not stop it without social distancing measures.
Heat and humidity have been suspected to be factors that affect the rate of infections, with some believing that extreme conditions could stop it entirely.
Most hard-hit countries by the pandemic so far have been in the northern hemisphere, where it was winter when the global outbreak began. However, some hot countries such as Brazil, Indonesia, Singapore and Qatar have suffered significant outbreaks as well.
Much research has been done on the matter, which is increasingly relevant as the northern hemisphere — including Israel, Europe and the US — edges toward summer and the southern hemisphere nears winter.
The new working paper, written by researchers from Harvard, MIT and other universities, examined outbreak levels and weather conditions from 3,739 locations around the world.
It found that average temperatures above 25 degrees Celsius (77° Fahrenheit) were associated with reduced virus transmission. Every 0.55°C (1.8°F) above that was associated with a 3.1 percent decrease in the virus reproduction number — the average new infections caused by each infected person.
Humidity is also associated with an inhibition of the virus’s ability to spread, although the paper didn’t provide detailed numbers for that.
In total, at the height of summer, infection chances are 18% smaller than at the height of winter.
“The best way to think about weather is as a secondary factor here,” Harvard assistant professor Mohammad Jalali was quoted as saying by the Washington Post.