Coronavirus

Coronavirus News: Warmer weather, humidity and COVID-19

ByJeff Smith WLS logo

Tuesday, March 24, 2020

NEW YORK -- While COVID-19 has been spreading like wildfire in locations like Italy and New York, other areas have seen a much more gradual uptick in cases. Public health policy may very well be stemming the tide of the virus in those places, but the weather could also be playing a role.

An early analysis by scientists at MIT has found that the novel coronavirus is spreading more slowly in warmer and more humid climates. At least two other studies have drawn a similar conclusion, including one conducted in China before the aggressive lockdown began.

So far this is just an observed correlation and may not have predictive value going forward, but it also may be the slightest glimmer of hope as we head into the warmer months.

A possible explanation lies in the physics of tiny droplets -- you know, the kind that propel out of our mouths when we sneeze and cough. When it's warm and humid these droplets quickly gather moisture from the surrounding air, grow, and then simply fall to the ground. But when it's cold and dry, the droplets can stay suspended in the air for longer, making them more likely to end up in the respiratory tract of someone else.

Another factor may be Ultraviolet light, which intensifies with the steepening sun angle this time of the year. That light has been shown to degrade influenza as well as other types of coronavirus, but the jury is still out on this particular strain.

It's important to note that COVID-19 is still spreading in warm equatorial regions, and we shouldn't let our guards down even as we head deeper into spring and eventually summer. That's why the best course of action is to continue to follow the advice of doctors and public officials.