It's important to understand the limitations of the paper. the paper simply plotted a set of regions where the outbreak happened, and analyzed the growth rate in these regions vs the average climate in that region. Notably, it did not include areas where there was no growth (which coincidentally, are almost universally hot or tropical regions). If those were included, you'd have seen a much larger effect.

With that said, even with just including areas with the epidemic - it found a statistically significant effect. Just, as you note - not a significant effect (which doesn't mean that a significant effect might not exist)

When cases in northern Italy got to the hundreds, German news were full with the position has been that Coronavirus was like influenza with a strong seasonal component. This was because the national plan for the disease included that idea. However, since Monday March 9th, they have adjusted it. This [1] is a (german-language) statement from Monday by a scientist involved in that effort. He mentions a study from the USA, but doesn't give any details that make the paper easily findable. The only study I could find was this [1] one. It studies the same topic and has a similar conclusion, but might not be the one that the change was based on. Relevant part of the abstract:

> Here, we examine province-level variability of the basic reproductive numbers of COVID-19 across China and find that changes in weather alone (i.e., increase of temperature and humidity as spring and summer months arrive in the North Hemisphere) will not necessarily lead to declines in COVID-19 case counts without the implementation of extensive public health interventions.

[1]: https://www.youtube.com/watch?v=DyK9PSsnCI8

[2]: https://www.medrxiv.org/content/10.1101/2020.02.12.20022467v...

> For both cities, humidity is relatively uniform year round.

There is no way humidity is relatively uniform year round in NYC. It gets very humid during the summer and very dry during the winter.

The relative humidity in NYC does not vary much from 60-65%. Absolute humidity is measured as grams water per cubic meter and is virtually never reported because what is relevant to human comfort is evaporation.

Indoor humidity in the winter is generally low because increasing the temperature without adding moisture is lowers relative humidy.

https://weather-and-climate.com/average-monthly-Humidity-per...

That's indoors. Outdoors, both cities are next to oceans, which tends to stabilize humidity.

In many parts of China, it will be 30C hotter and 50%p more humid in the summer than it is now. The combination might reduce R to virtually nothing.

In Japan, this could mean that it was the right decision to schedule the Olympics in the middle of summer after all.

I'm pretty sure that the Olympics will be cancelled. It's unlikely that we'll have a vaccine before then and Covid19 is well beyond containment at this point.

Abe is dead set on hosting the Olympics one way or another, so he might try to reschedule it... to a time of year when R is higher. :(

There will be all kind of athletes ill. Especially sucks if you're part of a team. I mean, for individuals as well, but as team you rely on each other's strengths even more. Gonna be interesting for sure.

The study uses relative humidity, which is affected by the dew point. While straight humidity is often consistent at least in the US, relative humidity fluctuates wildly. Relative humidity is what gives the muginess feel. Most of the US except the Rockies and most of the West Coast have way higher relative humidity in the summer months. NYC can get especially bad (or good in this case). In the South, that increase has already started.

Admittedly, it's not a huge affect, but taking your NYC example, the temperature alone will decrease the R0 by at least .5. I'll take that.

There are plenty of places that are hotter all year round, or have a larger temperature+humidity difference between seasons. Or was your comment only intended to address large US cities?

I think this serves to better explain the low case totals out of africa, but that might change in the near future.

Also, India which is not yet mentioned in the news, a country of 1+ billion people.

Also in Myanmar which shares the same border as China, 0 cases have been confirmed so far.

Why? Do you realize Africa is a huge continent with all kinds of weather right? https://www.timeanddate.com/weather/?continent=africa

Yes, but the average temperature in vast majority of the areas is higher than the avg temperature of say Europe. When we say Africa is warmer, it is a simplification simply by the virtue that its centroid closer to equator than Europe. Thus, we can say that it's warmer.

Side note: don't use rhetorical questions to respond to someone. It's demeaning. Rephrase "Why? Africa is a huge continent with all kinds of weather."

It's not demeaning, it actually adds color to the answer and makes it more engaging. I don't know what's up with HN's fetishizing of impassionate, humorless and snarkless style. Not everything has to be written like the IEE 754 specification.

Snarky comments explicitly discouraged in the official guidelines, which you can find at the bottom of this page.

You can be passionate and nice to people. This was mean.

There's a visualization here: https://twitter.com/JeromeRoos/status/1236729011889418246

Those temperatures are normalized to sea-level. If you go to say La Paz or Macchu Pichu expecting scorching weather based on that graphic you are going to have a bad time.