Relative humidity is one of those fun things to think about. RH indicates the amount of water the air can hold at the given pressure and temperature.

If the temperature goes down, the RH% goes up, because the air can hold less water in it. Likewise if temperature goes up, the RH% goes down, because the air can hold more water in it.

But things get dryer when temperature goes down and RH% goes down or stays the same. One of those things I noticed on my little digital guage when I turn on the mini split. Some of the water get yanked out of the air and drained outside.

4 months ago · 👍 cobradile94

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I run in hot weather so I eyeball dew point as a metric of how much my exercise outside is going to suck. Running with high temperatures (35°c) high humidity and a dew point of 24°c is going to suck because no matter how much you sweat it's not going to cool you. · 4 months ago

relative humidity is a hard to understand metric for humans. i use absolute humidity in my air quality monitoring these days and it makes a huge difference. it tells me how good or bad it is for me and my garden beyond the level of detail i can feel myself. easy to tell relative humidity as a human (proxy: temperature) but hard to get a feel for absolute humidity, here the data helps a lot!

my approximation:

absolute_humidity = 6.112 * pow(2.71828, (17.67 * temperature_c)/(temperature_c +243.5)) * relative_humidity * 2.1674) / (273.15 + temperature_c · 4 months ago