Posted by julosflb 7/1/2025
Still, it's hot. My daughter's school actually suggested parents keep their kids home today, as they aren't equipped for this heat.
Reminds me of when my colleague from Sri Lanka said that kids there will be sent home if the temperature drops below 16C. That’s a decent summers day in Scotland. We struggled to sleep last night after a sweltering 21C yesterday. I think I might burst into flames at 42C.
Think more like 16C at night feels colder than 16C during the day. The temperature in official thermometers is the overall air temperature in the shade which don't benefit from this overall radiating heat.
And of course humidity is also a huge part of how cold it feels. Which is why temperatures around 0C feel colder than -5C (because below zero the air humidity goes away).
You need much colder for this to happen. Google says:
Water vapor, even in freezing temperatures, doesn't instantly freeze into ice unless it comes into contact with a surface or the temperature drops extremely low (around -40°C).
The relative humidity of the air in winter at it's coldest point during a cycle is almost always 100% where I live.
Businesses open to the public and offices almost universally have AC, though, except maybe for mom and pop shops, so you definitely can go to the mall or the movies to get some fresh air.
The best place to go during weather like this is actually a grocery store: Picard, which only sells frozen food and so you get the escaped chill from the freezers.
This has worried me since I was a child. If everyone has AC it's a race to the bottom as it gets warmer and warmer, AC has to work harder, using more and more energy etc. You end up with hellhole cities where you can't be outside at all. It's simply not sustainable. We have to do other things like having green spaces, less tarmac, shutters on windows etc.
[0] https://www.euronews.com/green/2023/08/30/fact-check-is-air-...
Localised to alleyways etc the effect can probably be even worse.
The night time re-radiation has the effect of bringing the min closer to the max readings, and so making it look as if temperatures are going up, even when max temps aren't changing much. The same effect can't be seen in rural places where there's less tarmac.
Installing AC is actually not allowed in many places ( because of urbanism laws)
Only possible AC is those single hose mobile units which are wildly inefficient and close to useless while burning energy.
FWIW at least in the US (and I can't imagine they wouldn't be available worldwide) there are also dual hose portable AC units which can perform fairly decently, at least far better than single hose. I needed to use one for awhile at an old office (I think it was a Whynter model) and it was effective. There are also more exotic portable units that use water as the fluid dump, but that requires having a sufficient water source that you can utilize, and probably isn't going to be doable in a residential unit in a city. We had a couple at the chemistry lab I worked in 10-15 years ago that hooked into the lab water lines.
If you are worried about the local heat generated by the air conditioners themselves, there are new coatings and panels that can radiate that heat directly to space, for example https://www.skycoolsystems.com/. Also just removing a few parking spaces and replacing them with green space can help at a city wide level.
That's also only the operation of the things, their production and transport involves global chains of mining, shipping etc. and all the solar panels would be the same on top of that
Compare with data centers running entirely off grid, powered by tens of massive gas generators.
In Florida, HVAC accounts to 40% of energy bill of the household.
40% of 15% is not that much, even if everyone is using AC.
Just because you can make it look small by focusing on the percentage doesn't change that. At the end of the day it means, if we accept these numbers, that the total national energy usage would go up by around 7%. That then gets multiplied across France Germany, The Netherlands, Poland, Belgium, the UK & Ireland etc., to the point that the total power usage is as if we suddenly had another entire country.
And keep in mind while considering any of these numbers that our current 100% is already much higher than where we need to be at to avoid widespread ecological disasters. We need to be reducing our usage not saying "well it's only a few percent more."
EDIT: I didn't search too long but I found an article from a few years ago talking about the limit being 27 degrees. https://www.elnacional.cat/es/economia/sanchez-limita-aire-a...
It’s basically performs optically like snow. Paint doesn’t work because it gets dirty too fast, films can incorporate anti-fouling tech.
Delivery companies are already putting these on their vehicles (look at the top of UPS trucks in the US, if there is a giant white rectangle, that’s it).
In the evening, say 19h00, the sun is low and it's quite pleasant out. ("It's a dry heat," as we say!) I always forget how far north Paris and Versailles are: the sky still has some light past 22h30 this time of year.
Keep cool and stay safe, mes amis !
In warmer countries that heat usually dissipates by the time you go to sleep because the homes don't have as much insulation.
Since I left last Saturday, the heat got close to 43 and birds are falling from their nest, knocked out by the high temperature. Good luck to anyone there.
Night really is the worst, I don't care about the day, personally.
Me I see a gradual increase since the 50’s, with the very latest year being very low (20 degrees) probably because the dataset has not yet been updated for this year.
How do you read it?
I'd expect a bit more statistical knowledge here...
Used to be every 2 years in my childhood.
Both the duration and average and maximum temperature are all lower now compared to my childhood.
Is that enough statistics for extreme temperatures not being that extreme compared to previously? At least in my country?
What agenda do you think people have that are long dead?
If you distrust everything you can measure it yourself. I am still in youth and even I can see changes myself. There used to be snow in the winter and now it's rare for example. Yes that is weather not climate; I don't live long enough to see climate changes. But there are oil paintings from 300 years ago. Are these fake?
Genuine question: How do you know, that people who know climate change is made-up are trustworthy and don't have their own agenda?
Please avoid snarky tropes like this on HN.
I think climate research is orthogonal to any political agenda, i.e. opposing private transportation and meat consumption doesn't follow from accepting that the climate is getting warmer and the validity of political agendas has no effect on the authenticity of climate research data.
We know the effect of urban heat islands, stations sitting issues, mercury to thermistors upgrade transitions, time of observation bias, etc.
What we do with this data is a political situation, as the world is in a cooling cycle globally: https://www.climate.gov/media/16817
We have the technology to mitigate all of this, but not a critical baseline of education in the population to make the necessary sacrifices.