[Tetsu Tekubi]

I thought I'd compile this info into a thread of its own sans all the hoopla from the other recent threads to make it more readable/referencable.

Preliminary info:
This occurrence refers to the fogging seen behind the glass of a new or recent model that hasnt been opened or suffered severe trauma. Its possible to still happen after a properly done battery change but the O-ring should be checked first, just in case. The occurrence happens when a warm watch is exposed to a significant change in temp. eg. cold air/water.
The questions about this occurrence tend to spike around the same time every year ie. autumn in the northern hemisphere where the chances of going from a warm building/car to the cold outdoors is highly likely.

Casio's acknowledgement:
This can be found in the user manual (this was taken from a GA2100 manual)...

The inside surface of the watch glass may fog when the watch is exposed to a sudden drop in temperature. No problem is indicated if the fogging clears up relatively quickly. Sudden and extreme temperature changes (such as coming into an air conditioned room in the summer and standing close to an air conditioner outlet, or leaving a heated room in the winter and allowing your watch to come into contact with snow) can cause it to take longer for glass fogging to clear up. If glass fogging does not clear up or if you notice moisture inside of the glass, immediately stop using your watch and take it to your original retailer or to an authorized CASIO service center.

...and on Casio's support/FAQ website

https://support.casio.com/en/support/answer.php?cid=009001014001&qid=51548&num=4

Emailing Casio will also garner a similar response.

Note the distinction between "fog" and "moisture", in their terminology, "fogging" refers to water vapour ie. water in a gaseous state (ie. water in the air that you cant see till it condenses - when the temp drops below the dew point), and "moisture" refers to water in a liquid state that has entered the watch externally. In this context, it also distinguishes "nothing to worry about" and "take it to a service center".
Also note, the water content in the fogging is not enough to form drips, if it is, you have more than just fog.

The replication experiment:
Ive experienced the fogging in the wild a few times while on holidays to the snow or colder climates but there's very little chance of replicating it in nature here so I used water to recreate the temp. shift.
----
The experiment is to recreate a typical occurrence of going from inside (~21C) to outside (~7C).
The other thing to factor in is body temp, which depending on what youre wearing/doing could easily raise your skin temp and subsequently the temp of the air inside the watch* so to compensate for that, I measured my wrist temp for about 3min till the temp stopped fluctuating. 32C is about average for extremities.
Room temp was around 24C and I had done little to no exertion.
* - side note: its why models with a temp sensor need to be off your body for a period of time to adjust to the ambient temp

I prepped two bowls of water, one with warm and one with cold.
I waited for the temp to become steady on both. You can see the remnants of a couple ice cubes in the cold bowl, I left them in knowing it would warm faster than the warm bowl would cool.

In goes the Afrog. I also grabbed the gf8250 and a gulfy for comparison re: another frog and another model with a crown.

I left them there for about 15-20min then dunked them in the cold bowl. Temps had shifted 1-2 degrees but it was bringing the numbers closer, not apart so I wasn't too concerned.

This is watch from the creator of other thread for comparison

Bit less noticeable on the 8250 cos of the lighter coloured background but it happened to another premium model just the same. I went a second dunk with the Afrog and it had just enough warmth for more fogging (tho it cleared a lot faster). obviously if the temp difference remained the same, the effect would continue.

This effect varies between models and country of origin but as casio says, its within their operating parameters and classed as normal.

The DIY remedy:
If you cant live with it, it is fixable to some degree by going to a dry air environment eg. Aircon'd room and opening the case for 20min or so. I don't think rice is necessary cos the amount of air in the watch is so small and the number of water molecules attached to those air molecules would be even less.

Further reading:

Dew point - Wikipedia

en.wikipedia.org

Additional info:
RE: water droplets that makes it look like the condensation is on the outisde in the above photos

- Water droplets cause refraction of the light and cast their own shadow, having a light coloured background helps too. They can also have spectral highlights on the outside -and- inside. Its a clear bubble after all and light is truly magical.

- The pics I posted were the ones that had the best view of the fog cos that was the whole point of the experiment, the others where I did a quick dab with a paper towel (i didnt want to skew the result by rubbing my warm thumb over it) had a little too much motion blur or missed focus, again, just wanted the best view of the fog.
Here's one where its wiped cleaner but the fog is not as noticeable

• Condensation forms initially on the warm side of the surface, if you breath on your glasses, the condensation doesnt appear on the other side.
• If condensation were to form on the outside it would be noticeably uneven and the process would have to been performed in reverse ie. watch made cold first then going to a hot air environment (hot water wouldnt work as it would wash the condensation away)

Additional test:

From wiki on ISO 6425:

• Condensation test. The watch shall be placed on a heated plate at a temperature between 40 and 45 °C until the watch has reached the temperature of the heated plate (in practice, a heating time of 10 minutes to 20 minutes, depending on the type of watch, will be sufficient). A drop of water, at a temperature of 18 to 25 °C shall be placed on the glass of the watch. After about 1 minute, the glass shall be wiped with a dry rag. Any watch which has condensation on the interior surface of the glass shall be eliminated.

I guess he could try that with his watch.

I did this test as well and found its a pretty weak test for condensation. You need more water and a greater difference in temps to see any results. I believe most watches would be able to pass this easily.

If you have more factual info feel free to add it but lets try to keep the anecdotes, hearsay and other brands/types of watches to a minimum ?
This experiment is very easily to replicate and I welcome others to give it a try themselves.

---------------------------
UPDATE: 30/11/20
Experiment #2
Some minor tweaks to the original experiment.

Prelim info:

• Instead of soaking the whole watch to get it up to temp. I simply used the one straight from my wrist. So instead of everything being the same temp, this will replicate how the top of the crystal is constantly cooled by the ambient air it is exposed to.
• in the first experiment I didn't really focus on how I dunk it into the cold water, it varied from fully submerged to mostly. This time I tried to keep it only on the crystal ie. Submerging it about half way. I only did half the crystal so it was easier to see the contrast between fog and no fog. Easier said than done trying to hold it within mm of the sweet spot depth.
• I made sure I wiped the crystal properly before taking photos since this was a source of contention in the first one.
• to eliminate any (albeit unlikely) variables from a watch that had been worn about 10 times, the test subject is brand new, straight out of the box. Worn for about 2 hours before testing.
• room temp was about 23C, tested near an open window, outside temp was about 19C and breezy at midnight.
• Cold water bowl was ~8C. wrist/watch temp as per the pics ~30C

I don't know about anyone else but the results were unsurprisingly unsurprising.

Looks very much like what I and the OP experienced originally

Conclusion:
Does light fogging occur? Yes.

Is light fogging bad? No, if it goes away after the temps have equalised.

Is there proof this will ruin your G? still none.

Will Casio accept a return and replace? Yes, as per a single reference case. Result will probably vary between countries, retailer, staff and possibly the model in question.

Is it worth being without your new watch for weeks if they replace it? up to the owner.

Will it occur on a brand new one or whatever condition the replacement is in? Most likely, as shown here with a brand new model. Original owner still waiting on his replacement.

* WARNING: This thread has unfortunately been derailed with alot of discussion on irrelevant watches and conditions, proceed with caution beyond this point *

 

[GaryK30]

Thanks for the dedicated thread on this topic and the experimentation involved.

Regarding the DIY fix, since the GWF-A1000 owned by the original OP has a monocoque design, I guess opening the case in best left to Casio. This is much easier with a panel back or a screwback.

 

[Rocket1991]

Tetsu, as engineer i calculated few things and i put findings in other thread. Here them again. Yes watch will form some picograms of fog from air inside if you cool it to 7C even without heating it. That part is absolutely not necessary.
No, your experiment does not replicate problem OP of the other thread had.
Normal non defective watch on the wrist should not form any fog. What more, fog should disappear once watch is heated from 5-7C to ambient room temperature of temperature of the wrist which is 32C.
As far as watch is hermetically sealed (i assume divers watches are) and you deal only with air inside.
If you have even single drop of water penetration things become really foggy. What more fogging will stay.
That the gist of my post from other thread.
Bottom line your experiment is correct and there is no way you won't get fog following what you did. Yet, it don't prove what divers watch which was worn and put under running water from faucet and retained fogging is performing as it should.

Also, fogging on the glass is lesser of your problems since you get water on the electronics, cell and all internal components as well.
So i would strongly advise against repeating ice bucket tests.
Only thing it proves is that table from handbook of Chemical Engineering is working but it's known and repeatedly proven fact for more than a century.

 

[FROG]

I think Rocket and Tetsu are both right.

Tetsu's experiment really is designed to prove that internal condensation can occur given the right circumstances. I disagree that the circumstances that Tetsu is testing is indicative of actual day to day use. Going outside in cold weather with a watch on your wrist is not in any way similar to submerging a watch into water at 7C. Not even close. But that said, the experiment is a valid one.

I think it's important to note that some folks that experience internal fogging do so without literally dunking their watch in frigid water

I have owned a few watches in my life, and spent nearly a decade in Minnesota with its associated winters. I have not once had a watch fog internally on me. Not once. I have had several leak to the point where water droplets were literally on the internal side of the crystal, but I count those as gasket failures.

Again: Good experiment, but it only proves what it tests, which is not indicative of actual watch use.

 

[Tickstart]

OP, do the quoted ISO-test of condensation so we can get the hell out of here.

 

[Rocket1991]

I took 50m WR fashion watch outside at -30C and for 4 months at -20 or so.
No fogging whatsoever if all it does sit under glove and occasionally you look at the time.
Not a diver mere Skagen.

 

[WES51]

I very much appreciate OP Tetsu Tekubi 's experiment as well as his time and writing involved. But I'm not sure I can arrive to the same conclusions.

Although I have not had many watches in my life, I don't ever recall any of my WR watches that I had ever fogging up internally and I have lived in cold climates half of my life. So for that reason alone I have hard time to consider fogging up normal in circumstances when the watch is actually worn by a user.

I took this picture just a few days ago. Before going in the water, the watch has displayed near body temperature and a short time after going into the water the watch has displayed the temperature of the water. So this was easily a quick 20C temperature drop. Yet no fogging what so ever.

Also, in the past, I have done many (unrelated) tests on my GWG1000 and on my PRW6000, placing them from an approx 75F room into our freezer, so to about 0F.

During these tests, I don't recall observing any significant fogging inside these watches either (maybe a little bit in the center of the crystal) and I used to have them inside the freezer up to 2.5 hours long.

As a quick update recent reference, I have again put my PRW6000 into the freezer from a 75F room and left it there for 10 minutes. When I have opened the freezer door, the watches internal temperature meter was showing 42F measured, which is normally lagging behind, so the true temperature of the watch case may have been likely even a few degrees lower.

No internal fogging what so ever. When I have opened the freezer, the watch crystal was crystal clear. Of course it rapidly started fogging up from the OUTSIDE as soon as I took it out of the freezer and it got in contact with the warmer moist outside air. But again, only from the outside, which I could keep wiping away.

 

[Rocket1991]

It you take air at 23C and relative humidity of 40% (35-40% is usual for clean room type of manufacturing) it will have that much water content.
If you look up when that much water content will pass due point (essentially when fog forms) it will be around 5-7-9C. Depending on how much actual humidity was present
pretty much like this just there are far more accurate graphs and tables.

Air - Maximum Moisture Carrying Capacity

Maximum water content in humid air vs. temperature.

www.engineeringtoolbox.com

As you cool it down more and more...more water will come out as fog.
Considering minuscule internal volume of the watch and mere grams of water per cubic meter you should expect 1/1000s of the gram to appear. Pretty much nothing but fog is a fog.
Even single drop of water is much greater quantity so if you have it inside you may expect far more fogging since your humidity inside the watch will be maxed to that at 32C or so whatever your watch has on your wrist. This way you can expect fogging to appear around 17-20C or so and be more excessive and/or never go away.
My point here from all science and engineering points of view if you have water inside you will see far greater fogging. Makes sense. Right.
Also no matter what if you cool factory air to below 5C fogging will also appear. How much.... it depends. Should not be much and for that to occur whole watch and i do mean whole watch including every part and air inside should go down to said temperature. Which will never happen when your watch is on your wrist and you anywhere above 0C.
Even if you below freezing point of water and you literally did not put your watch to freeze for 20 min or more it still will be above 5-7C. Also, fogging occurs when hot humid air meets cold surface which is quite opposite to what will be present when warm watch facing cold air in the winter on under tap water.
So as far as you wear watch literally nothing should happen as far as there is no water inside.

I heard many stories about how some things do cross the boundaries of violent and unpredictable turbulence which creates pressure far greater than 100m of water when you move your hands inside water. I also had some discussions in scientific community about validity of results and some sudden appearance of them where it seem impossible. Thing is physics and thermodynamics are true science unlike history, politics of sales pitch it works according to certain rules and principles which don't give a ding about your views of the subject unless we go quantum. So if something which should not happen happening i will look for more probable reasons. Which in case of fogging will be presence of water in any other form apart from air.

As far as i understand ISO routine it's not looking for fogging due to humidity inside the watch but rather water penetration due to thermal expansion.

 

[Tetsu Tekubi]

Thanks for the dedicated thread on this topic and the experimentation involved.

Regarding the DIY fix, since the GWF-A1000 owned by the original OP has a monocoque design, I guess opening the case in best left to Casio. This is much easier with a panel back or a screwback.

good point esp. since frogs are recommended as "service center only". in saying that, the Afrog is just as easy a backplate model, it just has a few extra screws

 

[Tetsu Tekubi]

No, your experiment does not replicate problem OP of the other thread had.

obviously its not exactly the same, cos its almost summer here but the temp change is similar and most of all, its repeatable and measurable.
if you have a better way to do it, please do so and post your results here

Normal non defective watch on the wrist should not form any fog

are you saying all the watches i tested are defective? or more so, are you saying casio knows their watches are defective so they put the disclaimer in the manual to stop ppl from suing them?

What more, fog should disappear once watch is heated from 5-7C to ambient room temperature of temperature of the wrist which is 32C.

exactly what happened and exactly want casio states.

fogging on the glass is lesser of your problems since you get water on the electronics, cell and all internal components as well.

of course, -IF- water is getting in, no problem with the vapour thats already in there.

Also no matter what if you cool factory air to below 5C fogging will also appear. How much.... it depends

exactly. tho i did it at 7C, probably closer to 10C by the time i did the last dip.

Should not be much and for that to occur whole watch and i do mean whole watch including every part and air inside should go down to said temperature. Which will never happen when your watch is on your wrist and you anywhere above 0C.

youre right, its unlikely but that wasnt the test. the test was for the watch to be around 30C

fogging occurs when hot humid air meets cold surface which is quite opposite to what will be present when warm watch facing cold air in the winter on under tap water.

for dramatic effects like in the shower, yes, but its clear that it doesnt have to be that hot or humid. theres clearly enough water molecules in the factory air for it to condense on the cold surface ie. the glass when its exposed to cold water or air.

So as far as you wear watch literally nothing should happen as far as there is no water inside

nothing should happen but obviously sometimes it does. right, theres no water in a liquid form inside.

So if something which should not happen happening i will look for more probable reasons. Which in case of fogging will be presence of water in any other form apart from air.

are you saying its more probable that a bunch of brand new premium dive watches (amongst the many other regular models) are defective? from a manufacturer that has an excellent track record when it comes to build quality? even tho theres never been any reports of brand new seals failing?

 

[Tetsu Tekubi]

I think Rocket and Tetsu are both right.

Tetsu's experiment really is designed to prove that internal condensation can occur given the right circumstances. I disagree that the circumstances that Tetsu is testing is indicative of actual day to day use. Going outside in cold weather with a watch on your wrist is not in any way similar to submerging a watch into water at 7C. Not even close. But that said, the experiment is a valid one.

I think it's important to note that some folks that experience internal fogging do so without literally dunking their watch in frigid water

I have owned a few watches in my life, and spent nearly a decade in Minnesota with its associated winters. I have not once had a watch fog internally on me. Not once. I have had several leak to the point where water droplets were literally on the internal side of the crystal, but I count those as gasket failures.

Again: Good experiment, but it only proves what it tests, which is not indicative of actual watch use.

def. wasnt testing day to day use (impossible where i am, even if i wanted to!), just a condition that was similar to what the other person had experience and something that would be reasonably common, repeatable and measurable. "not in any way similar"? 7C is 7C, so id say thats pretty similar and it was a quick dunk, leaving it submerged for too long would equalise the temp too much and the effect wouldnt be as noticeable, if at all which would negate the whole point of the experiment ie. to show that it can happen under similar conditions. but yes, as i said, depending on the watch, the factory and prob even time of day it was built, some may never experience it but thats not to say it doesnt happen and if it does, that its defective. experiment aside, why do you think casio would put this note in their manuals? do you think theyre selling defective products and are trying to dodge their responsibilities? i certainly hope not 😥

as a side note, i was giving a couple watches a clean on the w/e, gave them a good soak in a hot bowl of water (over 60C, maybe 65, i think thats what my water heater is set at), took them out and ran them under cold water as i gave them a bit of a scrub and sure enough the fogging appeared as well 🤷‍♂️

 

[Tetsu Tekubi]

OP, do the quoted ISO-test of condensation so we can get the hell out of here.

i did thanks to your reference! i wish it was that simple lol

 

[Tetsu Tekubi]

I very much appreciate OP Tetsu Tekubi 's experiment as well as his time and writing involved. But I'm not sure I can arrive to the same conclusions.

Although I have not had many watches in my life, I don't ever recall any of my WR watches that I had ever fogging up internally and I have lived in cold climates half of my life. So for that reason alone I have hard time to consider fogging up normal in circumstances when the watch is actually worn by a user.

I took this picture just a few days ago. Before going in the water, the watch has displayed near body temperature and a short time after going into the water the watch has displayed the temperature of the water. So this was easily a quick 20C temperature drop. Yet no fogging what so ever.

Also, in the past, I have done many (unrelated) tests on my GWG1000 and on my PRW6000, placing them from an approx 75F room into our freezer, so to about 0F.

During these tests, I don't recall observing any significant fogging inside these watches either (maybe a little bit in the center of the crystal) and I used to have them inside the freezer up to 2.5 hours long.

As a quick update recent reference, I have again put my PRW6000 into the freezer from a 75F room and left it there for 10 minutes. When I have opened the freezer door, the watches internal temperature meter was showing 42F measured, which is normally lagging behind, so the true temperature of the watch case may have been likely even a few degrees lower.

No internal fogging what so ever. When I have opened the freezer, the watch crystal was crystal clear. Of course it rapidly started fogging up from the OUTSIDE as soon as I took it out of the freezer and it got in contact with the warmer moist outside air. But again, only from the outside, which I could keep wiping away.

fogging only occurs if the temp drops below the dew point, clearly it didnt reach that value. same way its not going to occur if youre doing the experiment in reverse, ie. warm air outside the watch. the effect you witnessed however is the same tho, just on a greater scale.

 

[FROG]

do you think theyre selling defective products and are trying to dodge their responsibilities? i certainly hope not ?

I definitely don't think that at all!

Do I think some watches make it out of QA with some minor failures? Statistically, yes, I think it's an inevitability. Is every case of fogging a problem with the watch? No. Is it a sign that Casio is a bad company? No way!!

But is it ok to ask for a watch that doesn't fog internally when I go outside and back indoors? I think so. We just can't ignore the personal, real world evidence that most watches do not fog on the interior of the crystal even in extremely cold weather. I must not refute the validity of my own experiences

I have troll PTSD, and I, like you, have seen people take stuff to the extreme and start bashing companies when there is even a hint of an issue with a watch. That's why I think your test is good and useful.

 

[WES51]

fogging only occurs if the temp drops below the dew point, clearly it didnt reach that value. same way its not going to occur if youre doing the experiment in reverse, ie. warm air outside the watch. the effect you witnessed however is the same tho, just on a greater scale.

This has been already correctly brought up by @Rocket1991. I don't disagree.

However I believe your lab experiment setup is far too extreme and appears result driven. Yes, it may prove that condensation can be induced in extreme circumstances, however those are far from anything that anyone may experience who is wearing any watch.

Like someone has mentioned in the beginning of this thread, I too think that the test should be done according to ISO 6245 and that is all. Pass or fail.

 

[Rocket1991]

Tetsu, i am saying if your watch on your wrist does fog and stay this way it 100% defective no matter what i think about Casio i would think same about any watch from any company.
If watch fogs too much for what i expect from it will mean only one thing
There is more water inside than you would expect from air at 30-40% humidity at 22C (AC manufacturing).
There are other reasons i think there is far more water than you can see inside due to physics and construction of the watch.
Are your watches defective or not it's for you you to be judge of it.
They are your watches not mine.
Now for whom your type of experiment is relevant? Probably only for these brave people who dive under the ice in arctic/antarctic and any other place. Where water is coldest and consequently watch will see about 0C .
Also it may be relevant for these dudes.

Would one drop of water damage your watch? No i don't think so. Would it affect functionality? No. Should it be inside? No. Would it cost too much in this scenario to replace every watch which fogs to Casio... yes. Is there are interest for Casio to BS their way out? Yes. Would i expect it from any other company? Yes.That how warranty works.
By the way any diver watch has Service Center only written somewhere because servicing and testing after service is more rigorous for this type of watch.

 

[Tetsu Tekubi]

I definitely don't think that at all!

Do I think some watches make it out of QA with some minor failures? Statistically, yes, I think it's an inevitability. Is every case of fogging a problem with the watch? No. Is it a sign that Casio is a bad company? No way!!

But is it ok to ask for a watch that doesn't fog internally when I go outside and back indoors? I think so. We just can't ignore the personal, real world evidence that most watches do not fog on the interior of the crystal even in extremely cold weather. I must not refute the validity of my own experiences

I have troll PTSD, and I, like you, have seen people take stuff to the extreme and start bashing companies when there is even a hint of an issue with a watch. That's why I think your test is good and useful.

statistically, theres always a chance but those chances are so minute esp. when it comes to seal failures on new Gs, let alone brand new yamagata PPL models.

sure its ok to ask for things but if its something thats known then its less about asking and more about accepting reality.

we also cant ignore the personal, real world evidence that under certain conditions, it can and does happen. i too can not refute the validity of my own experiences, the experiment or casios words. i also wouldnt call 7-10C extremely cold (tho most ppl in my city would say anything below 20C is extremely cold lol)

exactly why i thought doing this little experiment was a good way to dial back the raging mob. didnt want it to turn into another rangeman lug "issue" lol
instead of a bunch of hearsay, i wanted to put something simple yet quantitative together. you said the experiment proves what it tests but thats not exactly right cos i wanted to replicate the conditions the other person had so basically wanted to prove that the same watch in similar conditions would yield the same result. i also expanded the experiment to include other models to prove that it wasnt related to the watch.

i honestly dont know what else i could done differently, it seemed pretty straight fwd to me at the time. now spend WAY more time on it than i had ever envisioned or would have liked! lol thatll teach me for being proactive! haha ?

 

[Tetsu Tekubi]

However I believe your lab experiment setup is far too extreme and appears result driven. Yes, it may prove that condensation can be induced in extreme circumstances, however those are far from anything that anyone may experience who is wearing any watch.

far too extreme by using pretty much the identical parameters when it occurred naturally?
far from anyone wearing the watch... apart from the guy that was? lol
was havent the watch at body temp. then going out into ~7C too extreme and far from what someone would experience?
what would you have done differently to replicate what he experienced? ie. wearing a watch on his wrist and going outside to a 7C day

Like someone has mentioned in the beginning of this thread, I too think that the test should be done according to ISO 6245 and that is all. Pass or fail.

like i said, did and reiterated, i also did the ISO test and it didnt show any fogging but i also said, this would be a poor test to view this kind of fogging cos thats not what the original wearer did (or what anyone would do in normal conditions) re: a single drop of water - but as rocket said, its liking designed to test other things.

 

[Tetsu Tekubi]

i am saying if your watch on your wrist does fog and stay this way it 100% defective no matter what i think about Casio i would think same about any watch from any company.
If watch fogs too much for what i expect from it will mean only one thing
There is more water inside than you would expect from air at 30-40% humidity at 22C (AC manufacturing).

i agree 100% but that was never the point of the experiment or what has happened, the fogging cleared

Are your watches defective or not it's for you you to be judge of it.
They are your watches not mine.

what about all the other new or unopened watches that have been posted here and on facebook, are they defective?
if they were defective, why are ppl only complaining about it in winter? wouldnt it be worse in summer when they go swimming and the watch is properly submerged for long periods of time? wouldnt it get worse as more water enters the watch?

Now for whom your type of experiment is relevant? Probably only for these brave people who dive under the ice in arctic/antarctic and any other place. Where water is coldest and consequently watch will see about 0C .

not really cos i didnt put it in 0C cos the original poster said he went out in 7C temp so thats what i gauged it on. its relevant cos i used pretty much the exact same conditions as him.
how else should i have done it?

theres alot of naysaying and unrelated info here but no suggestions or alternative solutions. not sure why my experiment is so flawed when all i did was replicate it as close to the original as possible but i am more than happy see the results from others

 

[Rocket1991]

Tetsu your experiment shows yes there is moisture in the air and if you coll it down there is a fog. Yet under normal use of watch the only way to get to same results will be either swim with the icebergs or put your watch outside your clothing in the winter. Which is far from any normal use.It's right experiment just not representative of the problem OP had.
I also pointed to if i see my watch fogging under these normal conditions i would call manufacturer if watch is under warranty.
Long time ago my friend told about a friend who bought Omega (at the time and still it's huge deal) for some reduced price and found it fogged after shower...
My instant reply was real and non defective Omega don't fog in shower.
If your watch stay with the fog on your wrist that means amount of water in the air inside the watch rose 4-5 times from where it should be or was.

In many years owning many watches i don't remember any of them fog. Regardless of literally deserts, mountains, tropical islands or -30C winter i did exposed them to. I am literally talking 100s of watches. It's not like i did not seen fogged watches i just recently got one Seiko chrono for cheap i intend to take apart and clean and just passed on other Seiko with same problem because it's not really impressive to get diver style watch with singes of fog. In case of chrono i know buttons are culprit which lead water in. Just fogging did not happen to me and new watches i bought.
I once almost got into accident when my car windows fogged on inside to condition of 0 visibility. I was lucky and road was straight with nobody present in my lane. Fogging does happen given opportunity just not in the watches i own.