Is the temperature sensor any good for others?

When I get ‘ice cream head’ it’s cold and that’s usually around 13C. When it gets to 15C or thereabouts it’s time for a swimrun wetsuit. From 18C on I’ll go togs only. My Garmin usually correlates pretty closely with those sentiments and reasonably well with posted temperatures. 

We have to bear in mind that water temperature is not a constant. The temperature posted might not be the same as where you swim. The best way to be sure is to take the temperature of the water where you swim and free of any skin contact. Anything else is approximated.

Dr Phil said:

We have to bear in mind that water temperature is not a constant.

It's not. There's a lot of things that affect it. There was no skin contact, it was over the wetsuit.

But:
16, 16, 17, 17, 16, 15, 16, 15 °C
vs.
13.6, 14.1, 14.7, 13.6, 14.0, 13.2, 14.4, 13.6

And the feeling.. It's off. I don't know is Polar right, but at least it's closer. I would guess that's there's also some extra in the Polar numbers.

But that comment that the temperature sensor is primary for used for calibrating barometric sensor kind of makes sense, so it seems that it isn't supposed to be very accurate as it also only reports rounded temperatures with no decimals.

Have to just ignore the data as I don't remember it being correct even once, in any activity. Checked some winter activities, the Garmin weather data says: "-12,8 °C", the recorded data is average 4,4 °C and I wear it over the jacket.

I just thought that the swimming would be the best case to get it working and showing real temperatures, but doesn't seem like it. Today running Garmin avg. 22,5. Weather data 15.

So went and ordered Tempe.

No idea yet, where one could put it nicely especially on swim(run)'s so that it would also measure the temperature as the signal will propagate approx 10cm under water.. 

Probably if one would want good constant data it would need some DIY wrist wrap, or somehow attached to watch's wrist wrap. We'll see when it arrives.

jmto said:

Probably if one would want good constant data it would need some DIY wrist wrap, or somehow attached to watch's wrist wrap. We'll see when it arrives.

I've been using (and unfortunately losing) Tempes for years.  It should go under your watch strap just fine but for this use-case I think I'd put it under the swim goggle strap.

How often does it send data? So is there any change of it getting the data while out of the water. Ok. quick Google says once in every 2s. So yes, that probably might sometimes get the data transferred when not in the water.

But now I also started thinking how fast is it to react as if it's in and out of the water how does that affect the measurement and now that I think that also could explain the too hot readings as there seems to be some algorithm at least in the watch itself that it takes some time to change the temperature.

So always out of water it's going up, and in the water it's going down..

So should Tempe also be in the water for the whole time, but then where to get the watch to read it. This probably needs some testing :) 

It might send data every 2s but it doesn't update data that often.  Seems like only every 2 minutes or so based on the graphs I'm used to seeing.

A Tempe only transmits a new temperature every minute.  That's why the battery can last a year running 24/7

Do you have some source for your minute claim? I did quick Google and it said 2s. And now Googling more.. 4s, 30s.. 

HR is every second and those can also last pretty long depending on your running.

Or it's written to FIT every minute, like it rounds the temp for every previous minute or something, that doesn't really proof how often does it send the data, but at least the accuracy in the FIT is for every minute which is kind of smart to avoid it being really noisy and spiking.

As if it would send it every minute those might get lost and especially if swimming probably no chance of getting data if not really close.