Are u sure hot weather hinder the virus spread? After your post I researched a bit and found this article. Some of your hypothesis makes sense since we had enough tourist from China and Europe when rest of the world were under pressure to contain it. May be the humidity and temperature will kill in the surrounding or surfaces, but if it comes around close to another human cell- I think it will just attack. Around the world, there would be countries having colder weather when we are having hot weather. I think it’s has more to do with isolation n personal space. But I appreciate your thought; kinda makes sense.

The temperature theory doesn't really hold up given what's happening right now in much of Southeast Asia," said Tikki Pangestu, a professor at Singapore's Lee Kuan Yew School of Public Policy."People in Europe hope warm weather will kill the virus. I doubt this will be the reality."
The coronavirus, which causes a respiratory disease called COVID-19, has infected almost 170,000 and over 6,500 have died.Though a limited amount is known about the new virus, some of the symptoms show similarities with winter influenza, which is more widespread in colder temperatures, although this is partly attributed to people crowding together inside.Places where the virus has been felt most severely, such as Wuhan in central China, northern Italy and parts of the United States, share similar climates and temperatures.