Channeling my inner @NanoRaptor

An emergency spare part just arrived for my PC. It has a bright yellow sticker that says "Caution: Static sensitive devices. Not to be handled by unauthorised personnel."

Am I authorised? Am I even competent?

I don't know, but I peeled the sticker off before opening it just in case.

I'm a big believer in knowledge, having been acquired, is worthless without sharing it. So thanks to @rycuda I looked up the Stoll Equation, which is an empirical formula (https://journals.ametsoc.org/view/journals/apme/50/11/jamc-d-11-0143.1.xml Roland Stull 2011) that can be used to estimate the wet bulb temperature from dry bulb temperature and humidity without faffing around with putting a wet sock on a conventional thermometer.

Why is that important? Well it's an estimate of what temperature you can achieve by evaporative cooling alone, and next week is going to be in the 30s across all of Europe, with France promising to be hitting 40 ºC in large areas. If you can't cool yourself then you're going to have a bad time, and the wet bulb temperature this seems to happen at for humans is about 31 ºC.

What can you do about this? If you have Home Assistant and a sensor that's feeding in temperature and humidity, you can use this to make a template helper:

{{ ((states('sensor.temperature')|float) * atan(0.151977 * ((states('sensor.humidity')|float) + 8.313659) ** 0.5) + atan((states('sensor.temperature')|float) + states('sensor.humidity')|float) - atan((states('sensor.humidity')|float) - 1.676331) + (0.00391838 * ((states('sensor.humidity')|float) ** 1.5) * atan(0.023101 * (states('sensor.humidity')|float) )) - 4.686035)| round(1) }}

Just remember to replace sensor.temperature and sensor.humidity with the appropriately named sensors, and you should be good to go. I've added rounding to 1 decimal place, largely for convenience, because otherwise it produces enormously long floating point outputs that cannot possibly retain any sort of accuracy.

If you come up with any enhancements of your own, please put them here in the replies. (Edit: I just realised this only really applies to Celsius so if you come up with something that works for Fahranheit feel free to add it back)