IMD predicts wet days ahead as studies show correlation between COVID-19 and hot/humid weather

Vibha Sharma
Tribune News Service
New Delhi, April 24

Amid increasing evidence of direct correlation between the deadly COVID-19 and hot and humid weather, the good news for India is that the IMD is predicting reasonably wet days and above normal temperatures for most parts of the country in days to come.

Some studies have again reiterated that warmer temperatures and humid weather significantly damages the novel coronavirus.

And on a day Health Minister Harsh Vardhan’s positive outlook, including that India had been saved from the Stage 3 or the community transfer stage, the general feeling is perhaps apart from lockdown and management, its weather conditions may also have helped.

If the studies hold good, the good news is weather conditions will continue to favour India’s COVID-19 fight.

According to the IMD, due to continued moisture incursion, strong wind convergence and conducive upper level features, fairly widespread rains will continue over parts of east and northeast and also West Bengal, Odisha, Jharkhand and Bihar.

Rain activity is also expected to increase over Kerala, Andhra Pradesh, Telangana and Tamil Nadu over the next five days.

Moisture influx from the Arabian Sea and low level easterlies from the Bay of Bengal are likely to cause rains over Uttarakhand and Himachal Pradesh between April 26 and 28 and plains of the northwest, mainly Punjab and Haryana, Chandigarh and Delhi, over next two days

While rains are expected to continue beyond April 30 as well, many parts are reporting above normal temperatures.  

According to this latest report from the US, “sunlight kills COVID-19 and warmer temperatures and humid weather significantly damage the virus, measured in terms of the virus’ half life or the time it takes to cut its potency in half”.

The interesting part is that though researchers are working on the link since the virus hit the world, this particular report from the US Department of Homeland Security is being called the “first official stamp” on the correlation. 

“Our most striking observation to date is the powerful effect that solar light appears to have on killing the virus, both on surfaces and in the air. We’ve seen a similar effect with both temperature and humidity as well. Increasing the temperature and humidity or both is generally less favourable to the virus,” reports quoted Bill Bryan, chief of the science and technology directorate at the US Department of Homeland Security, as saying.

While in a room at 70-75F ( around 21 C to 23 C) temperature with 20 per cent humidity, the half life of the virus is about an hour outside it cuts down to a minute and a half, very significant difference when it is hit with UV rays, he said.

This is good news for a country like India blessed with sunny days approaching pre-monsoon and monsoon days.

Also according to IMD, from April 30 to May 6 cumulatively rainfall is expected to be normal to above normal across Western Himalayan Region and maximum temperatures increase by 1-2 C in most parts. 

As India heads towards a particularly hot season, researchers expect COVID-19 to follow the “marked seasonality” shown by its genetic cousins prevailing among humans since centuries.

In other words the corona family is generally more volatile between December and April, giving a good reason to believe to researchers that soon its impact will lessen.

Earlier a preliminary study of progression trends by Massachusetts Institute of Technology (MIT) researchers had indicated lesser cases in hotter zones.

Qasim Bukhari and Yusuf Jameel of MIT concluded that  90 per cent of the transmissions until March 22 occurred in regions with temperature between 3 C and 17 C and absolute humidity between 4 to 9g/m3 (grams per cubic metre). 

“Wherever the temperatures were colder, the number of the cases started increasing quickly. You see this in Europe, even though the health care there is among the world’s best,” they said.