[WhiteSage]

In the east coast of Spain we have had great weathee (25+ degrees celsius) and it didn't seem to greatly influence transmission speed :(

[devdas]

The numbers so far suggest you need tropical heat and humidity to slow down transmission speed. That would need to be 35C+ weather, and no air conditioning.

[whatch]

Before I've read you message I was sure that dry air slows down transmission speed. But indeed, it's humidity https://papers.ssrn.com/sol3/papers.cfm?abstract_id=3551767