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I just experienced 38 degrees heat with 30% humidity here in Berlin just a few days ago. and then 28 degree heat with 60% humidity. I'll take 38 degrees at 30%

I just experienced 38 degrees heat with 30% humidity here in Berlin just a few days ago. and then 28 degree heat with 60% humidity. I'll take 38 degrees at 30% humidity every time. It was fine. At 60% humidity, you are sweating non stop and it's uncomfortable because not enough of it evaporates. You feel sticky, hot and miserable. At 30% humidity, sweating cools your body really effectively and while taxing, you recover quickly in the shade. 38 degrees (slightly warmer than you) is no joke. But at that humidity, I prefer it over much cooler temperatures with higher humidity. The combination of high temperatures and humidity is lethal.

ant6n 4y ago
I grew up in Berlin as well and never minded the heat, because it was usually dry. But in the last decade or so we seem to have more of these hot and humid days, which makes me wonder… why doesn’t this startup target consumer dehumidifiers first, it would seem like an easier market when u have some newfangled technology with magical properties. Unless it’s really expensive.
acchow 4y ago
Curiously, if you do the wet bulb conversion: 38C@30% humidity = 24.4C 28C@60% humidity = 22.2C
- zagrebian 4y ago
  What do the numbers on the right hand side mean?
  - bisby 4y ago
    From https://www.omnicalculator.com/physics/wet-bulb https://www.omnicalculator.com/physics/wet-bulb > Wet-bulb temperature is the lowest temperature a portion of air can acquire by evaporative cooling only > Our bodies sweat to cool off, but, because water evaporates slower in more humid conditions, we cool down a lot slower in humid conditions. Basically, "what is the absolute coolest you can get from evaporative cooling via sweat."
- bisby 4y ago
  So that 10C difference only feels like 2C difference, but comes with the complications of being all sticky, which might make you feel more miserable overall despite being technically cooler. Also, I don't know enough about wet bulb, but would it be possible that if humidity is higher, that sweat evaporates more slowly, and accumulates rather than just evaporating? If sweat drips off your body rather than evaporating off, do you still get the cooling effect (is it the releasing of sweat, or the evaporating that cools you?). Walking through a park on a summer day and a lab environment are going to be a bit different. Basically, my question is, does wet bulb temperature accurately represent the human body, or is this a spherical cow moment?
  - andreareina 4y ago
    Less evaporation happening is exactly the mechanism by which the wet bulb temperature is higher the more humidity there is. Sweat dripping off doesn't invalidate the model because heat is still being pulled away at the maximum rate, it's just that the body is expressing more moisture than actually needed.
    - bisby 4y ago
      I was more thinking of things like surface area. At a certain point, once the sweat starts pooling, the sweat to evaporation ratio goes down (since it can only evaporate at the surface, which is further away from the skin, so now sweat is also insulating). And the point of evaporative cooling isn't that sweat is taking heat away from the body through contact heat transfer. Evaporation actually uses heat for the phase change, which means that a single drop of sweat will pull heat out of your body through standard heat transfer. And if it drips. then it has just pulled that heat away. If it evaporates, it will actively pull even more heat away. Which is why wet-bulb temps can be below ambient. If the sweat drips, you don't get the evaporation benefits. So if you sweat to the point that you are dripping, I would have to believe that you wouldn't hit the ideal wet-bulb temps, and would thus be hotter.
dghughes 4y ago
I live in south-eastern Canada today it was 35C which is something I've never seen here. And the humidity at one point was 90% which is typical since I am on an island. Thankfully it went to about 70%. I felt tired it wears you out even 35C is OK but any humidity over 60% is terrible. My entire childhood up until ten years ago a 30C day here was a very hot day that came maybe once per summer but most years never.
michaelcampbell 4y ago
SE US checking in. It's routinely 75% humidity or above almost year round here. And yes, it makes both the hot and the cold worse.
greyhair 4y ago
Any dew point above about 70F/21C is going to be uncomfortable. Any dew point above about 75F/24C is can be dangerous. Dew point determines how much body cooling you can achieve through sweating.

ant6n 4y ago

I grew up in Berlin as well and never minded the heat, because it was usually dry. But in the last decade or so we seem to have more of these hot and humid days, which makes me wonder… why doesn’t this startup target consumer dehumidifiers first, it would seem like an easier market when u have some newfangled technology with magical properties. Unless it’s really expensive.

acchow 4y ago

Curiously, if you do the wet bulb conversion: 38C@30% humidity = 24.4C 28C@60% humidity = 22.2C

zagrebian 4y ago
What do the numbers on the right hand side mean?
- bisby 4y ago
  From https://www.omnicalculator.com/physics/wet-bulb https://www.omnicalculator.com/physics/wet-bulb > Wet-bulb temperature is the lowest temperature a portion of air can acquire by evaporative cooling only > Our bodies sweat to cool off, but, because water evaporates slower in more humid conditions, we cool down a lot slower in humid conditions. Basically, "what is the absolute coolest you can get from evaporative cooling via sweat."
bisby 4y ago
So that 10C difference only feels like 2C difference, but comes with the complications of being all sticky, which might make you feel more miserable overall despite being technically cooler. Also, I don't know enough about wet bulb, but would it be possible that if humidity is higher, that sweat evaporates more slowly, and accumulates rather than just evaporating? If sweat drips off your body rather than evaporating off, do you still get the cooling effect (is it the releasing of sweat, or the evaporating that cools you?). Walking through a park on a summer day and a lab environment are going to be a bit different. Basically, my question is, does wet bulb temperature accurately represent the human body, or is this a spherical cow moment?
- andreareina 4y ago
  Less evaporation happening is exactly the mechanism by which the wet bulb temperature is higher the more humidity there is. Sweat dripping off doesn't invalidate the model because heat is still being pulled away at the maximum rate, it's just that the body is expressing more moisture than actually needed.
  - bisby 4y ago
    I was more thinking of things like surface area. At a certain point, once the sweat starts pooling, the sweat to evaporation ratio goes down (since it can only evaporate at the surface, which is further away from the skin, so now sweat is also insulating). And the point of evaporative cooling isn't that sweat is taking heat away from the body through contact heat transfer. Evaporation actually uses heat for the phase change, which means that a single drop of sweat will pull heat out of your body through standard heat transfer. And if it drips. then it has just pulled that heat away. If it evaporates, it will actively pull even more heat away. Which is why wet-bulb temps can be below ambient. If the sweat drips, you don't get the evaporation benefits. So if you sweat to the point that you are dripping, I would have to believe that you wouldn't hit the ideal wet-bulb temps, and would thus be hotter.

dghughes 4y ago

I live in south-eastern Canada today it was 35C which is something I've never seen here. And the humidity at one point was 90% which is typical since I am on an island. Thankfully it went to about 70%. I felt tired it wears you out even 35C is OK but any humidity over 60% is terrible. My entire childhood up until ten years ago a 30C day here was a very hot day that came maybe once per summer but most years never.

michaelcampbell 4y ago

SE US checking in. It's routinely 75% humidity or above almost year round here. And yes, it makes both the hot and the cold worse.

greyhair 4y ago

Any dew point above about 70F/21C is going to be uncomfortable. Any dew point above about 75F/24C is can be dangerous. Dew point determines how much body cooling you can achieve through sweating.