"warm weather may have an effect on transmission" and "a warm city is dealing with infections" are not mutually exclusive statements.
And for the record, as of a little over a week ago, there were only a dozen cases in Singapore according to the WHO. Even if they were mutually exclusive, Singapore isn't exactly the best example.
Exactly. The comparison with Indonesia is interesting, which has a similar climate, but isn't as rich or developed as Singapore.
Air conditioning is actually very conducive to colds and the like. When you go from outside to inside you're usually sweaty and the air conditioning tends to make you too cold until you dry out. I've caught way more sniffles in the tropics than in the freezing climates.
Anecdotally, I flew from Bali to Singapore today and there seemed to be a lot more sniffles and coughing in Singapore. In Bali the architecture is very open with lots of fresh air, scooters being popular for transport whereas in Singapore they tend more to sitting together in air conditioned boxes of various types (buildings, busses etc).
The real takeaway from the 74 Million piece is that information about HVAC in American schools is difficult to come by. It would certainly be interesting to look at COVID-19 in schools vis-a-vis A/C, but good luck prying information from the school districts about either infections or air conditioning. Perhaps it would be easier in a tropical country like SG where A/C is more of a necessity than a luxury.