From the comments, on coronavirus and humidity
I am not convinced by the humidity hypothesis, as I don’t see it having much macro explanatory power globally, but I find the questions very important. On New York City, I tend to blame all those cramped indoor spaces combined with bad ventilation systems, but that too is an unconfirmed hypothesis. Anyway, here are the words of Daniel Hess:
Here is Alex’s source post, and there are a few interesting responses in the ensuing discussion.