It does seem that maybe virus doesn't like the warm weather. Not that it can't be transmitted in warm weather, but it's a little bit less infectious.
“For every increase in heat of 1 degree Celsius (the equivalent of 1.8 degrees Fahrenheit), we are seeing about 2% decline in transmission,” public-health expert Ali Mokdad, the chief strategy officer for population health at the University of Washington’s Institute for Health Metrics and Evaluation, told ABC News. “We find this relationship in our data and possibly it would be more when the
weather warms up this month.”
Does warmer weather slow coronavirus?
Very interesting.
"A study from engineers at the Massachusetts Institute of Technology, still awaiting peer review, offered a direct comparison between the spread of coronavirus and local environmental conditions. It determined that places with high growth rates like Italy, New York, and Washington state exhibited “weather patterns similar to original hotspots of Hubei and Hunan (China),” where the pandemic started. Those locations were averaging temperatures between 37 and 50 degrees Fahrenheit at the time. By contrast, places with warmer climates like Saudi Arabia, Australia, Qatar, and Taiwan have exhibited lower growth rates.
The researchers used weather data over 10-day periods between Jan. 22 and March 21 and concluded that the lower number of COVID-19 cases in tropical countries might be due to “warm-humid conditions, under which the spread of the virus might be slower as has been observed for other viruses.”
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The study’s authors, in an email to ABC News, wrote their “main findings pointed towards the role of humidity as most important.” They did, however, stress that “there were found COVID cases even in the most humid places on earth, so the only way to stop the spread of COVID is to take precautionary measures.”
Brownstein agreed, saying “while there likely could be an environmental relationship, we can’t count on humidity alone to slow down the epidemic over the summer period.”
IHME, whose coronavirus-projection model is one of the most widely trusted in the field, is now planning to factor in weather-related variables going forward, Mokdad told ABC News.
Professor Mark Urban, an expert in biology at the University of Connecticut, recently authored a paper concluding that ultraviolet light could slow the growth of coronavirus.
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“When we look across the US and the world, we find that in places where the ultraviolet light was lowest in the preceding weeks, the COVID-19 growth rate was the highest,” Urban said of his findings, which have yet to be peer reviewed.
Access to fresh, outside air is another possible factor experts are looking at -- both because warmer weather sends people outside and because buildings in warmer climates often have more outside air circulating indoors.
“It’s logical that more temperate climates are more likely to have architectural designs that are conducive to outdoor engagement, to free flowing spaces that connect to the outdoors like larger windows, more access to fresh air and more access to daylight,” according to Professor Kevin Van Den Wymelenberg, who runs an institute at the University of Oregon focused on creating buildings that support human health.
