Thanks! That is causation though. Annual temps really have zero impact, as you can see on that map there are a hundred other places that fit those same temps that aren't circled. It's a certain seasonal temp range which is likely due to UV exposure that has the bigger impact. All of the stuff we put together shows the virus tends to spread faster in areas that have long periods with temperatures between 40-60 degrees without huge temperature swings. Places like New Orleans are in ideal range from the end of November to mid March. I actually think peak infection rate in New Orleans is over with and now we are just seeing the fallout and think we will actually peak in the next couple weeks while the spread begins to slow.
Cities farther north with coastal influences that moderate temperatures during the winter and summer months are the ones we think are the hardest to combat. Places like Seattle and Vancouver that experience long periods in this weather norm with high percentage of cloud cover are really tough. NYC had an adnormally warm winter putting them in this risk area for a long period this year. Combine NYC with travel routes and population density it is why it became our #1 City in the US with cities like Milan, Paris, London and Madrid for huge outbreaks. The one city on our "top 10" list that his been able to really hold ground is Seoul, South Korea. Other cities that have done surprisingly well are Dublin (and Ireland as a whole), Glaskow and Lisbon to a degree. Ireland and Scotland shut things down really fast and hard. Seoul has a young population and was very aggressive with early testing, contact tracing and isolation. Lisbon was slower to react and has more cases but so far has been able to hold off a catastrophic outbreak.
Unfortunately there are a lot of cities that are just now starting to get into peak virus spread. Cities like Boston, Detroit, Twin Cities, Chicago, Milwaukee, Buffalo, Erie and Cleveland are places to watch in the USA in the coming weeks/months. In Eurpoe there are a lot of places that fit the bill for long duration peak temps and minimal UV exposure that could run into early summer and then after a brief relief period jump right back into those zones with an early fall season. All of those cities and places will be the canary in the coal mine for the 2nd wave.
What we don't understand is why the virus tends to spread slower in winter of colder areas that have even less UV exposure. Places like Berlin and Moscow or MSP and Detroit in the USA. Our guess was people tend to go out less, have a lot less skin exposure with so many people in those location wearing gloves and layers of clothes. Which also makes us think that more tranmission from surfaces happen than most people think. Plus those tend not to have the huge international hubs due to frequent poor weather days which may have reduced seeding. It could be the virus just doesn't do as well in freezing temps but we think that is unlikely. Ontario and toronto have been the most outlier of the cold weather places but they avoided early big outbreaks while temps were still cold. Toronto is going to be a city we think has a lot of problems moving forward.