I just deployed a Mastodon bot that posts forecasts for the most dangerous upcoming heatwaves

You can follow it at

@heatwave

To determine how dangerous a heatwave is, it uses wet-bulb temperature, which is the temperature that a body can be cooled to by evaporation

Sweating works to cool you because generally the wet-bulb temperature is lower than body temperature

As wet-bulb temperature increases and approaches body temperature, people can no longer cool themselves by sweating and will die

@eob @heatwave I need to implement this in my weather station software.

@drwho @heatwave This is the formula I used:

https://github.com/eobrain/heat-wave/blob/main/wetbulb.js

Strictly speaking, wet-bulb temperature can only be measured by a physical device, but this formula seems to be a reasonable estimate based just on temperature and relative humidity

heat-wave/wetbulb.js at main · eobrain/heat-wave

Find upcoming heat waves somewhere in the world. Contribute to eobrain/heat-wave development by creating an account on GitHub.

GitHub
@eob @drwho @heatwave WBT is defined theoretically and as such it can reliably be calculated from the air temp and humidity. Measurements are less exact because no measuring instrument is perfect. Back in the day every weather station measured humidity based on the measured WBT, but these days the tech has gone past that and it's no longer necessary.