Tropical temperature is 64F or 18C and above
It is a percentage of the amount of vapor at a specific temperature to the absolute humidity. For a cubic meter, it is
Actual amount/Total amount that air can hold
Warm air can hold more.
Cooler air can hold less
Jan 21 to Jan 23, 2020 (non intervened transmission.)
1 degree C increase in temperature lowered R0 by 0.0225
1% increase in humidity lowered the R0 by 0.0158
the virus was more contagious in northern China, where temperatures and humidity were relatively low and less contagious in the warmer and more humid cities in the country’s southeast coast.
Temperature, Humidity and Latitude Analysis to Predict Potential Spread and Seasonality for COVID-19
March 5, 2020
Sajadi said, “It couldn’t have been bad luck that these particular places were hit.” He explained, “This virus is acting as a seasonal respiratory virus. We could be wrong, but with the data we have, we think that is the most likely scenario.”
Will Coronavirus Pandemic Diminish by Summer?
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83% of testing has been in non-tropical countries (30N and above).
90% of the cases are recorded in the range of 3C to 17C.
72% of the cases are in the areas with humidity between 3 to 9 g/m3.
Most tropical countries have not tested as extensively as northern countries. (Mobeen’s comment: what about China and South Korea? South Korea did a lot of testing. South Korea is 35.90N)
Several countries between 30N and 30S such as Australia, UAE, Qatar, Singapore, Bahrain, Qatar, and Taiwan have performed extensive testing per capita and the number of positive 2019-nCoV cases per capita is lower in these countries compared to several European countries and the US.
Current data, although limited, suggests that it is extremely unlikely that the spread of 2019-nCoV would slow down in the USA or Europe, due to environmental factors, because a large number of cases have already been reported in the range of AH and T experienced by these regions for the most part of the year.
if, new cases in April and May continue to cluster within the current observed range of AH i.e. 3 to 9g/m3, then the countries experiencing monsoon, i.e. having high absolute humidity (more than 10 g/m3) could see a slowdown in transmissions, due to climatic factors.
Our results in no way suggest that 2019-nCoV would not spread in warm humid regions and effective public health interventions should be implemented across the world to slow down the transmission of 2019-nCoV.
“Wherever the temperatures were colder, the number of the cases started increasing quickly,” said Qasim Bukhari, a computational scientist at MIT and a co-author of the study. “You see this in Europe, even though the health care there is among the world’s best,” Bukhari said.
Warm weather, humidity could curb rapid COVID-19 transmission, study shows
Coronavirus Outbreaks Could Become Seasonal Woe, Some Researchers Suggest