Hotter temperatures do not guarantee the cessation of all possible transmission of SARS-CoV-2, it impedes it in relation to the increase in temperature (and also ideally humidity, particularly indoors). It helps make everything else you might do for slowing the spread more effective and easier. There is very strong evidence at this point that SARS-Cov-2 is susceptible to the same seasonality factors as influenza. We're seeing this demonstrated all around the world simultaneously in warmer climates, from Mexico to sub Sahara Africa to hotter countries in Asia. It's why none of the major cities in Latin America are seeing the kind of infection rates as NYC or Milan (or as Wuhan previously did). It's why sub Sahara Africa isn't getting hammered (despite plenty of international traffic and trade, including previously from China, that should have massively spread it). It's why India still isn't seeing a massive explosion in cases, as has been feared since the beginning of the outbreak in China.
Check out: Mobile & Birmingham & Montgomery Alabama, the Western handle of Florida, Jackson Mississippi, look at other cities in Louisiana that didn't hold Mardi Gras (and one assumes those cities still got a burst of their cases from the Mardi Gras spread event).
Check out: Mobile & Birmingham & Montgomery Alabama, the Western handle of Florida, Jackson Mississippi, look at other cities in Louisiana that didn't hold Mardi Gras (and one assumes those cities still got a burst of their cases from the Mardi Gras spread event).