The map of the COVID-19 cases shows that that they are concentrated in temperate areas that have been experiencing winter. Regions that have tropical heat and humidity have seen surprisingly few cases of the virus.
For example consider east Asian countries, the South Korea, which has relatively cold winters, has had the largest number of cases (7869 cases, with 66 deaths) while the Philippines has seen relatively few (52 case, 2 deaths). Early spring weather may also be helping to reduce the number of cases in Wuhan and southern China.
In the US, the worst outbreaks have been in Washington state, California, and the New York City area which have low indoor relative humidity. More humid areas such as Florida (29 cases, no deaths) and Puerto Rico (zero cases or deaths) have seen far fewer cases even though they are popular destinations for foreign tourists.
Cold winter weather results in low relative humidity inside heating buildings, which is seen the annual flu season the US. There is also evidence that higher relative humidity reduces the spread of airborne viruses:
Warmth and humidity will return to the eastern US and Europe in coming weeks. That should help to slow the spread of the disease in those areas. Of course, any benefits will be temporary and the virus may come back with a vengeance in with the return of colder weather in the fall.
Do you think that humid conditions will reduce the spread of the coronavirus?
What implications are there for fighting the spread of the virus if spread is strongly related to climate conditions?