A new study uploaded to the research site SSRN finds that 90 percent of the coronavirus transmissions so far have occurred within a specific temperature between 3 and 17C (37 to 63F) and absolute humidity range.
For areas outside this zone, the virus is still spreading, but more slowly, according to the study by two scientists at the Massachusetts Institute of Technology.
The paper, which was shared with the public before it was peer reviewed for the benefit of public health officials, notes that even in warm parts of the United States, such as Texas and Florida, cases are not exhibiting the same growth rates as they have in New York and Washington state.
The best-case scenario, according to the study’s authors, is that the rate of spread in parts of the Northern Hemisphere will slow as temperatures warm and humidity increases.
However, they warn that if absolute humidity — the total mass of water vapor in a volume of air — is a more important factor in coronavirus transmission, then many cities seeing a surge in cases, including Boston and Paris, may not get much of a respite in the summer.
This is because these areas do not get hot and humid enough to significantly reduce the growth rate, outside of a small window in July.
The researchers caution that even in warm, humid regions, governments need to implement measures to slow the spread of the virus, since warm weather could inhibit but not eliminate the spread of the virus.
In these areas, “the general public should not take it as evidence that they can go around with their daily life and not take any precautions,” said study co-author Qasim Bukhari of the McGovern Institute for Brain Research at MIT.
The new MIT study is similar in findings to research published this month that also focused on the temperature and humidity link.
“Both of our studies show that areas with low absolute/specific humidity and low temperatures are those that are experiencing significant community transmission,” Mohammad Sajadi of the Institute of Human Virology at the University of Maryland School of Medicine, a co-author of a previous study, said via email to The Washington Post.
At least two other studies have come to similar conclusions — including one conducted by Chinese researchers at Beihang University and Tsinghua University.
The authors found that between Jan. 21 and 23 — before China’s authorities intervened to stop the spread of the deadly bug — the infection was more contagious in northern China, with low temperatures and relative humidity, than in warmer, more humid cities along the southeast coast, according to the Wall Street Journal.
Researchers in Spain and Finland found that the virus tends to spread in regions with dry conditions and temperatures between 28.3 and 49 degrees Fahrenheit, according to the Times. ■