Just how accurate are the F5x sensors? Is my device faulty?

So I've had my F5x since the offecial launch and I like it, though some inaccuracy here and there and minor missing or bugged up features I still enjoy the watch.

Anyway today I inspected an industrial size cool room with a controlled temperature of 2.8c. Anyway I'm excited as I can try the accuracy of the temp. Sensor, so before entering the room I noted that the watch was at 27c then after 20 minutes inside the cool room the watch only dropped down to 17c. What gives? The watch was totally exposed and wasn't covered at all as we used a sleeveless jacket.

So is my watch faulty or the F5x requires you to have hyperthermia before going down to accurate level?

You'll never get an accurate temperature reading when wearing the device as you're body heat alters the temp at there sensor.

The internal temp sensor is known to be "off" from ambient, due to the impact of your body heat on the watch and other factors such as wearing long sleeves, etc. It's main thing is to work in conjunction with the baro so the temp of the air inside the watch is into account for measurements.

It's not bad if the ambient temperature is about 98F though! :)

Even if you just take off the watch and set it on a table, it can take something like 20 minutes to fully adjust to ambient.

If you want better info, a tempe is the way to go. External and can be placed in a good spot for ambient, etc. It can be used while recording an activity or when you're not, etc.

In the app app store link in my sig, there's a widget called "temps", that's similar to the native temperature widget, but does a couple things it does. One, is that if you have a tempe, it will show you the readings from both on the same screen (you can see the difference in the two). Also, with a tempe, it can take a minute or so to connect when something like a widget is run, so this widget caches the last reading it saw from the tempe for 1-240 minutes and displays that while waiting for a new reading.

Only way to have an accurate temperature while wearing the watch is to pair with the TEMPE sensor