Here's a quick look at temperatures of the hot-spots around the world.

It's more for discussion purpose, than anything else. Plenty of inconsistencies for sure, but interesting never-the-less.
It seems interesting [at the very least] that almost ALL major outbreaks happened (and are happening) in geographical areas with low mean temperatures.
Apart from the Diamond Princess and California, there doesn't seem to be any major outbreaks in warmer "climates".

If there is a distinct correlation between low temperatures and COVID-19’s susceptibility to spreading, there could be a reasonable conclusion that when temperatures rise, the spread will slow and potentially cease. We can only hope.

Countries selected are the top 10 listings by confirmed cases from https://www.worldometers.info/coronavirus/
Interesting is that there are no countries in the Southern Hemisphere at the top of the list (Northern Hemisphere = Winter, Southern Hemisphere = Summer)

Notes:

- Temperature sources are average mean temperatures January and February taken from https://www.timeanddate.com They are not actual 2020 numbers, but averages from 1985-2015
- Temperatures are mean-temperatures for January, February, and March, in °C, showing daily low and high
- Region/cities of each country were chosen based on various factors, but mainly because they seem to represent their respective countries’ major outbreaks
- There seems to be a misconception that reported, confirmed cases represent actual and accurate current infections. This is FAR from the truth. Every country handles the criteria for testing differently, and there is a also a lack of testing kits. There is a significant delay in the actual number of infections vs. the reported cases.


Confirmed Cases by Country, Territory, or Conveyance
(taken around 9am, March 8, 2020)





1) CHINA; Wuhan
https://en.wikipedia.org/wiki/2019%E...mainland_China






SOUTH KOREA; Daegu
Most cases (~75%) are in Daegu
https://en.wikipedia.org/wiki/2020_c...in_South_Korea






IRAN; Qom
Limited information, but Qom believed to be a major source of the outbreak, especially early on
https://en.wikipedia.org/wiki/2020_c...tbreak_in_Iran






ITALY; Milan
Capital of the Lombardy region
https://en.wikipedia.org/wiki/2020_c...break_in_Italy






FRANCE; Creil
“As of 2 March 2020, 67 people were infected by COVID-19 in the Hauts-de-France region. This figure, the highest in France, was linked to a major cluster originating in the city of Creil, in the Oise, whose source remains unknown.”
https://en.wikipedia.org/wiki/2020_c...reak_in_France






GERMANY; Düsseldorf
North Rhine-Westphalia’s capital and close proximity to “Especially affected areas, as defined by the Robert Koch Institute“
https://en.wikipedia.org/wiki/2020_c...eak_in_Germany



SPAIN; Madrid
Spread out quite well across the country. Madrid = Capital.
https://en.wikipedia.org/wiki/2020_c...break_in_Spain





JAPAN; Sapporo and Tokyo
Japan is interesting; most cases are listed in northern, colder Hokkaido prefecture. But that is the whole prefecture not a city. Sapporo is included as the capital of Hokkaido, and Tokyo is included as it also has a high number of cases, but is more temperate
https://en.wikipedia.org/wiki/2020_c...break_in_Japan

Sapporo, then Tokyo




USA; Seattle and NYC
“Washington currently has the highest number of cases and deaths out of any state in the country,...”
https://en.wikipedia.org/wiki/2020_c...hington_(state)

NYC has the highest number of new cases two days in a row (as of March 8).
https://en.wikipedia.org/wiki/2020_c..._United_States

Seattle, then NYC




Anomalies:

- Diamond Princess
- California

Diamond Princess
(Officially 696 cases, 6 deaths)
It has been called a “petridish” and an incubator for COVID-19; the close [proximity] living conditions, the buffet-style food consumption, the centralized air-conditioning, the potentially unsanitary standards of the crew, etc. could all have contributed to the large number of infections.

California:
Needs further investigation. A few cases from Diamond Princess, but plenty of unrelated cases.
Remains one of the anomalies.