What the latest research says about summer's impact on COVID-19

Summer will not be a cure for the coronavirus, according to health officials.

Since the beginning of the coronavirus outbreak, researchers have raced to better understand how different types of weather could impact the spread of COVID-19.

Now that spring is moving towards summer across Canada, more research suggests summer could affect certain aspects of this virus. However, this won’t be a 'pass' to return to normal.


Researchers at the University of California recently explored how the built environment impacts the survival of the virus. They looked at homes, apartment buildings, hospitals, etc., to see how the virus thrives, and whether we can better dilute virus contamination indoors.

Their findings led them to believe that opening up the windows and letting in fresh air could help “dilute indoor contaminants, including virus particles,” essentially decreasing the risk of someone inside breathing in contaminated air."

Warmer summer temperatures will naturally urge people to open windows in their home and have better air ventilation. So this could be a seasonal positive leading to less contamination.

"Yes, open up your windows. Air circulation is a practice used in hospitals, especially with patients who have tuberculosis. However, COVID-19 is spread by droplets and has very little proof of airborne transfer," explains infectious disease specialist Dr. Chakrabarti, when asked about this research.

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“Viruses like SARS Coronavirus-2 are enveloped viruses,” says Matthew Miller, an associate professor at the Institute for Infectious Disease Research with McMaster University. “The outside part of the virus is composed of these lipids which are fluid and moist. The cold air helps those particles to hold together better than the hot humid air, which causes them to essentially dry up,” he adds.

However, the weather is not going to be the “silver bullet” that ends the spread.

“Waiting for the weather to make a big difference is not a substitute for things like social distancing, washing your hands, avoiding touching your face and keeping away from sick people,” Dr. Chakrabarti explains.


A recent study from Massachusetts Institute of Technology (MIT), “Will Coronavirus Pandemic Diminish by Summer?, confirmed many things previously known to doctors about the behaviours of viruses in certain types of weather.

In their report, the researchers concluded that “while influenza virus has been shown to be affected by weather, it is unknown if COVID-19 is similarly affected.”

While it is still not ultimately clear what effect temperature and humidity have on the coronavirus itself, nor on its transmission, researchers at MIT were able to find some promising results:

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  • the virus has a less effective airborne nature at higher absolute humidity levels

  • heat plays a role in breaking down the lipid layer of the virus - essentially its outer protective coating

  • lower number of cases in tropical countries might be due to warm-humid conditions

In their research, scientists took into account population density, government regulations, and testing abilities.

They concluded, “under any circumstances, we believe that large gatherings (both indoor and outdoor) should be avoided across the world.”


Even though some of these studies could create the idea of summer being a less severe season for the pandemic, doctors are warning people that summer is not a cure and that there is still much research to be done.

Health experts continue to stress that human actions will be the biggest driver in spreading or stopping this pandemic, at least until a vaccine is developed.

“The outbreak itself does have a tendency to drop off after a while,” says Dr. Chakrabarti. “We are likely to see more spikes even before the fall and winter. And that’s why it’s so important for public health to continue working on early identification.”

Miller also agreed that it is likely to see some “transient increases in cases,” as the world tries to return back to normal.

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Summer’s greatest benefit to this pandemic is likely the natural boost of happiness the season provides to many Canadians.

Be sure to watch the video that leads this article for more details on how warmer weather may or may not impact the novel coronavirus.