# Ambit temperature readings



## twelveone (Jan 18, 2012)

Is anyone getting accurate temperature readings on their Ambit? Mine is around 10°C too high. According to the user manual this is because the sensor is next to the wearer's skin. I'm not understanding the purpose of this feature if you need to take the watch off to get an accurate reading. I could see it being useful when cycling if the watch is clamped to the handlebars, but for most activities, the watch will be on my wrist. And besides, when I take it off my wrist the temperature reading doesn't change. Even when I leave it on my bedside cabinet overnight, the temperature is still way off. It's hot for the time of year here in the UK, but it's definitely not 28°C! b-)

From the manual:
_NOTE: If you are wearing your Suunto Ambit on your wrist, you will need to take it off in order to get an accurate temperature reading because your body temperature will affect the initial reading._


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## cobrapa (Mar 15, 2012)

Yeah, I think it's the least accurate on Ambit. I think it also has a really slow filter. When I went for a jog, from a warm house outside to ~65deg F, it shows a slow ramp down for the 10 minutes or so I was running. It's fairly linear the whole time. I'm not real impressed with their placement of the temp sensor.

I notice it is warmer than air temp as well, probably due to proximity of the skin.

I'm a little surprised it doesn't decrease overnight though. I'll have to look more carefully at mine.

Here's some run data:


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## Jeff_C (Feb 11, 2006)

This is the "issue" with all ABCs. 

I have said it before... I think the temp function is the least useful. 

I can't come up with any practical function for the temp function.

Can you?

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## Joakim Agren (Feb 12, 2006)

Jeff_C said:


> This is the "issue" with all ABCs.
> 
> I have said it before... I think the temp function is the least useful.
> 
> ...


When I am on vacation and want to know the water temperature then it can be fun to know the water temperature while swimming. The sensor will be accurate for temperature when in water. Also when on a food break then if you take of the watch and wait 20 minutes the watch will show the correct ambient temperature. So it do have some uses. But it is not very important, but I still like to have a temperature function out of curiosity. An on board thermometer is also critical for the barometric sensor since air density have an impact on interpreting weather/pressure trends.


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## Mystro (Oct 26, 2008)

It works well with camping or climbing at base camp. It works well for giving a temp reading inside your tent at night when hanging it in the tent. I have used it hunting in a similar way be attaching the watch to my treestand for a half hour.


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## Lost-again (Feb 24, 2012)

The temp sensor is actually used by the barometer to compensate the reading, that is why you find them on most ABC watches with a barometric sensor, so it has an important function not really for giving you a reading of air temp while on your wrist. However, if you take it off an attach it to your rucksack strap, you get an accurate reading!


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## Jeff_C (Feb 11, 2006)

Still not convinced... so you know the temp in the water... in your tent... or in your stand. So? 

Practical uses are imho so limited that the inaccuracy is a non issue.

I generally subtract about 15 degrees and its close enough for government work.

I mean even then who cares if its 76 or 78.

I just think the REAL needs for temp in the field is pretty limited. 

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## twelveone (Jan 18, 2012)

Could be used to check body temp and see if you're coming down with flu?


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## Jeff_C (Feb 11, 2006)

All depends on where you take it.... remind me never to buy a used core from you! LOL...


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## wydim (Feb 26, 2012)

Jeff_C said:


> All depends on where you take it.... remind me never to buy a used core from you! LOL...


I major LOL'd reading this !! ahaha used core.... bwwwaaaaaahahahahah


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## or_watching (Nov 13, 2008)

Lost-again said:


> The temp sensor is actually used by the barometer to compensate the reading, that is why you find them on most ABC watches with a barometric sensor, so it has an important function not really for giving you a reading of air temp while on your wrist. However, if you take it off an attach it to your rucksack strap, you get an accurate reading!


Lost-again has the right answer.

Accurate altimeter function requires knowledge of the barometric pressure and the temperature at the pressure sensor.

The "standard profile" for altitude vs pressure has assumptions for the air temperature (because the temperature of the air affects the pressure). When the altitude is computed for a given pressure if the temperature at the sensor is not the same as the 'profile" expects, then an adjustment is made in the calculation. this is useful to know the more extreme your elevation gain. for example: if you gained 5000 ft and wore your watch under your puffy jacket sleeve the whole time, the watch would make a relatively big adjustment for temperature because it would think, "gee, it's a lot warmer up here than I expect for a 5000 ft gain". If you wear your watch outside your clothes or even on a bare arm then on most days the temperature will match the standard profile and little adjustment for temperature is done by the watch. And for instance if there are unusual conditions, like a temperature inversion where the air temperature in increasing with altitude, then the watch will correctly compensate.

And what matters temperature-wise is the "change" or delta in temperature. and so a fixed offset from the absolute correct air temperature (e.g. +5C due to your body) at two different altitudes doesn't matter. Lesson: set your referense altitude (aka calibrate) with the watch on your wrist if you plan to take future readings on your wrist.

You can see an example of the "standard profile" in some of the Suunto documents. There for the uber enthusiasts who want do some extra calculations by hand when they are on an outing. In such a case you do want to know the "sensor temperature"
See pages 47-49 of the attachment. (pdf pages 49-51)

Other than that, it works pretty well to hang in the tent and see the temperature off your body.
View attachment X6_X6M_userguide_EN (Altitude Charts).pdf


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## Jeff_C (Feb 11, 2006)

Lost-again said:


> The temp sensor is actually used by the barometer to compensate the reading, that is why you find them on most ABC watches with a barometric sensor, so it has an important function not really for giving you a reading of air temp while on your wrist. However, if you take it off an attach it to your rucksack strap, you get an accurate reading!


Agreed... I never suggested, or didn't mean to suggest, the function was useless to the device... just that real world application was not nearly as important as the ABC functions.

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## wydim (Feb 26, 2012)

or_watching said:


> Lost-again has the right answer.
> 
> Accurate altimeter function requires knowledge of the barometric pressure and the temperature at the pressure sensor.
> 
> ...


or_watching, you're clearly an engineer, aren't you ? I know that because we seem to speak the same language.


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