>Keep in mind that a lot of us are not Americans and don’t know or care what trump is saying.
I'm also "not American" (I'm Scottish) and so shall continue to keep the fact that a lot of us are "not Americans" in mind.
That being said, "it’s quite possible that the Virus spread will stop as the weather warms up" implies the weather is going to "warm up", which is only relevant in the northern hemisphere. Half the planet is going to cool down.
More importantly, the CDC (yes, a USAian source), recently stated ""At this time, it is not known whether the spread of COVID-19 [the illness caused by the coronavirus] will decrease when weather becomes warmer." so asking for data, or at least why this statement was claimed as "quite possible" is very reasonable.
Finally, you claim that things will die down "based on prior coronavirus outbreaks, e.g. mers, sars" - here is a (peer reviewed, with abundant data) paper claiming the exact opposite of what you are claiming, specifically: "This study provided some evidence that there is a higher possibility for SARS to reoccur in spring than that in autumn and winter."
https://www.ncbi.nlm.nih.gov/pubmed/15709076
So again I have to ask: based on what data do you draw your conclusions?