> The framing (at least as I understood it) was more on the psychometric side - 24C@65% relatuve humidity _feels_ worse than 27C@45%RH It's complicated to quan

> The framing (at least as I understood it) was more on the psychometric side - 24C@65% relatuve humidity _feels_ worse than 27C@45%RH It's complicated to quantify, but in a sense 24C@65% is warmer than 27C@45%RH. Or rather, maintaining your body temperature is more difficult in the former than in the latter. The human body produces ~100W of heat, and the primary way to get rid of it in warm weather is evaporative cooling: at below 100% relative humidity water slowly evaporates, this takes energy and thus cools down the surface the water was sitting on. We use that by coating us in sweat and letting it evaporate. This is more efficient the lower the relative humidity is. The attempt to quantify this in a nice metric is the wet bulb temperature (what would a thermometer with a wet cloth around it show). 24C@65% is a wet bulb temp of 19.3C, 27C@45% is a wet bulb temp of 18.8C