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Comment by bobnamob | Hacker News Reader

To those citing weather as a likely influence, I'm not sure I agree.

Given the graph provided by the linked site, it looks like cases started really dipping in late August. August and September are still bloody cold in Melbourne, where most of the cases have been recorded. Additionally, Australia is heading into a La Nina summer, generally characterised by a slower onset of warmer weather and greater average rainfall.

Edit: Anecdotally, Adelaide weather for the last few months has barely registered as spring. Melbourne is typically a few °C cooler than Adelaide.

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There's a theory that relative humidity indoors modulates transmission.

At low humidity, water evaporates from droplets, making them lighter. The lighter they are, the longer they can stay suspended in the air.

At higher humidity it is more likely for droplets to accumulate more water, which makes them heavier until they fall down.

https://www.tropos.de/en/current-issues/press-releases/detai...

Yes, it was Winter and they were in a four month lockdown. Let me repeat, a FOUR MONTH lockdown. That is a bloody long time so anything but a huge dip during a four month lockdown would just be bizarre. Now they have summer, cases a low after a lockdown and due to the weather cases will remain low like we've seen in Summer across all of Europe, regardless what measures countries have taken. If Europe was to spend 4 months out of their Winter in lockdown, then cases will drop there too.

> Now they have summer, cases a low after a lockdown and due to the weather cases will remain low like we've seen in Summer across all of Europe, ...

Summer starts here in Australia in a month from now. (We'll then be contending with the return of bushfires.)

I think it's disservice to assert the weather is what will keep our case count low -- when a lot of people have gone through a whole lot of shit (and still are) to achieve & maintain the situation we now have.

I think there's sufficient contra-examples in both hemispheres to suggest that the weather is not a major factor -- though it is politically expedient & convenient to point at the weather to distract from mismanagement.

> I think there's sufficient contra-examples in both hemispheres to suggest that the weather is not a major factor -- though it is politically expedient & convenient to point at the weather to distract from mismanagement.

I'm not a politician, I'm not a nationalist, my birthplace is not the culture which I've been raised under, where my parents come from I've never lived and where I live now I have no ties whatsoever, so simply I don't care about country politics and trying to suggest anything different is the real disservice.

It's a fact that warm weather plays a huge role. In Europe we have seen a first relief during Spring and all countries have seen a huge dip in cases during their warmest summer months, completely irrespective of the countries individual measures. That's just a hard fact that you can't argue away in good conscience.

Furthermore, irrespective of how well countries have done, how many sacrifices people have done and what measures countries have taken (e.g. Germany vs. Sweden vs. UK vs. Czechia, etc.) all European countries see the same acceleration of cases. The only difference is the baseline where the spike starts, but the curve upwards is literally identical, so it further underlines that the weather has a bigger influence than any other measure except a full lockdown on the infection rate of coronavirus.

My point was that politicians that are incapable of managing this disease within their own borders would be happy to point to weather, as a way of abrogating responsibility. This claim is typically made without citation.

If people that repeat this claim, asserting it as fact, don't have citations -- then that's a different but related problem.

In Australia we got this under control through winter. Several states (South Australia, Western Australia, Tasmania, Northern Territory) had it so well controlled they had little if anything resembling strict lockdowns. Also through winter.

If 'all of Europe' (I'm not sure if you're talking mainland only there, or are including the very warm bits down the south, etc) is having the same results, then absent a control set to compare to, we can't know if that's an effect of comparable politics / culture, lack of controlled border controls, that a tipping point has been reached, or, as you say, 'because it's cold'.

A point for Germany: the current outbreak is much stronger than the one in March, even though we didn't have obligatory masks in March (they've been in effect since April; few people had them before they became obligatory). We had very few cases during the (pretty warm) summer (in the county I currently live in, there were zero cases in June). March peaked at around 5.5k on a single day, October peaked at ~13k with most days >5.5k.

Given that we have a lot more measures in place now (masks, distancing etc), something else has to play a role. February and March were unusually warm and sunny. I don't know whether that's relevant, but it seems unlikely that the counter-measures predict the peak - they are much stricter now than they were at the beginning of the year.

There were no real testing infrastructure in March. Everything was an unknown, and most people didn't get tested unless they showed serious symptoms and were close to hospitalization.

The current assumption in Norway, based on testing and WHO guidelines) are that we detect about 1/2 of the active cases through testing now, compared to 1/10 back in March. Applied to your numbers, the current outbreak in Germany is about a fifth of what it was back in March.

Be careful about assuming the numbers represent the same thing over time and between countries; in general the ratio of positive cases compared to the number of tests has changed a lot during the last eight months.

Some of the reports from the Norwegian health authorities has explicit notes about where reporting and testing criteria changed during the timeline.

Good point, testing might be a large factor. That would be very good news with regards to the danger of Covid-19, since it would lower the actual death rate massively.

From what I understand the current daily test capacity for Germany is about twice as large as it was in April. I do believe that they're still only testing those who exhibit symptoms or have been in contact with somebody who tested positive.

Germany was the one country in Europe that did have fairly decent testing infrastructure in place during the spring outbreaks, though. So that doesn't apply so much to them as it does to other European countries. It wasn't quite as good as it is now - looking at the RKI's stats, they did over 400,000 tests in the week at the end of March when test positivity hit its spring peak, compared to over 1.2 million the last few weeks - but they didn't have the massive ramp-up in testing that most other European countries did.

Speaking of test positivity, their all-time high is 9% and the most recent week for which information is available isn't that far off that at 5.6%, and I think that number's effectively a week old at this point. All indications are that Germany really, genuinely does have a bigger outbreak this time around.

It's also pretty easy to find counterexamples. For example, COVID numbers in India started exploding in May, which is also the hottest month throughout most of the country.

The trend for suppressing spread in the US isn't so much hot weather, it's temperate weather. Any time people are comfortable being outside, there's less spread. When it gets too hot for that (the South and Southwest over the summer) or too cold (the North, broadly, now) we see lots more spread.

Don't know if this trend holds outside the US.

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