Wet bulb globe temperature

I would also like to see a wet bulb globe temperature reading. This would be very beneficial for anyone working outside to measure heat stress on the body.

We that already and a Delta-T for Air Temp to Wet Bulb Temperature. This is displayed on the Android app at least.

It has wet bulb temp, but not wet bulb globe temp. Two different measurements.

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@glenngoddard I only see Wet Bulb Temperature. That is not the same as Wet Bulb Gloge Temperature (usually abbreviated as WBGT). There are a lot of links that go into more detail on WBGT … here is one … WetBulb Globe Temperature . Here is a wikipedia areticle … Wet-bulb globe temperature - Wikipedia .

That being said, if we had a better voting system, I would definitely use a vote for WBGT support … very useful (in my opinion, one of the better heat indices out there).


I didn’t realize there was a difference. I did find some estimate calculations for black bulb temperatures to help estimate WBGT. Since the weather stations don’t have the black bulb temperature it will have to be estimated to get the WBGT.

If you use Home Assistant and the weatherflow2mqtt integration, I am working on a PR to add WBGT. In case you do not and also to make it easier for developers here:

WBGT = 0.7Twb + 0.2Tg + 0.1Ta
WBGT is Wet Bulb Globe Temperature in C
Twb is Wet Bulb Temperature in C
Tg is Black Globe Temperature in C
Ta is Air Temperature (dry bulb)
The above equation is exactly the same for F

Tg = 0.01498SR + 1.184Ta - 0.0789Rh - 2.739
Tg is Black Globe Temperature in C
SR is Solar Radiation in Wm^2
Ta is Air Temperature in C
Rh is Relative Humidity in %
This equation as written will not work with F directly.

So…do we want Black Globe Temperature as an additional output, my initial guess is no. So.
WBGT = 0.7Twb + 0.2 * (0.01498SR + 1.184Ta - 0.0789Rh - 2.739) + 0.1Ta
simplified: WBGT = 0.7Twb + 0.002996SR + 0.3368Ta -0.01578Rh - 0.5478

The approximations I had previously found used Sun Azimuth to estimate Solar Radiation, we don’t have to estimate since we have the actual measurement from the Tempest.

I used Celsius for this since that is what most individuals in the world use, even if I don’t as a regular system. The conversion from Celsius to Fahrenheit is simple so it should not be an issue.


Having WBGT would be a selling point for Tempest since it could be used at facilities where there is outdoor physical activity taking place to monitor heat stress and eliminate a standalone WBGT tracker. A base level Kestrel 5400 Heat Stress Tracker is almost $500 USD.


Forgot to come back and update, but WBGT was added to @bjarne’s WeatherFlow2MQTT for HomeAssistant.

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Interestingly, the API has just had a new field added in the response for my weather station - wet_bulb_globe_temperature. I wonder if this means we will soon see it in the App / Website?

There is an update from less than a month ago at WeatherFlow-Tempest, Inc. | StartEngine that says they are working on putting WBGT into the product, so, looks like they are making progress on that plan.

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