undefined | Better HN

0 pointsDanielHB8mo ago0 comments

It is hard to explain to people who don't live in tropical countries, but 16C in Scotland means the sun is still up giving some radiating heat when it directly hits you or the building you are on. 16C in a tropical country means the sun is completely blocked and no direct heat coming towards you.

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).

0 comments

votepaunchy8mo ago

> 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).

user____name8mo ago

I think what they meant is humidity is lower when freezing, not necessarily zero.

bryanlarsen8mo ago

The relative humidity goes up when the temperature goes down. The water doesn't go anywhere, but the ability of the air to hold it drops, so the relative humidity rises until it hits 100% and water starts precipitating out.

The relative humidity of the air in winter at it's coldest point during a cycle is almost always 100% where I live.

j / k navigate · click thread line to collapse