When I take a hot shower, there is normally a fair amount of steam. However, I don't think the water coming out of the shower-head is actually boiling (unless I am mistaken).

Why is there water vapor in a hot shower?

  • 2
    $\begingroup$ You chose the tag evaporation. Does that ring a bell? $\endgroup$
    – 299792458
    Commented May 9, 2015 at 16:57
  • $\begingroup$ So is the water boiling? $\endgroup$
    – Tdonut
    Commented May 9, 2015 at 16:58
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    $\begingroup$ Related: How does water evaporate if it doesn't boil $\endgroup$
    – 299792458
    Commented May 9, 2015 at 16:59
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    $\begingroup$ Steam from the shower is mostly condensation not evaporation. The warmer than it's surrounding jets of warm/hottish water create warm very humid air near the showerhead. As the air moves around the rest of the shower and bathroom, it gets closer to room temperature and the colder air can't hold as much water, so it condenses in the form of steam. Similar process to how clouds form. If you were to take a 90 degree shower in 90 degree bathroom you wouldn't see as much steam. $\endgroup$
    – userLTK
    Commented May 9, 2015 at 20:03
  • $\begingroup$ Oh, and if we want to be technically correct, If you can see it, it's water droplets not steam and not water vapor. :-) $\endgroup$
    – userLTK
    Commented May 9, 2015 at 20:14

1 Answer 1


What you can see is not steam in the strict technical sense, even though it is commonly referred to as such. If you can see it, then it is probably water droplets floating in the air, somewhat like a cloud.

These water droplets can often be seen in the same places as steam is, since hot H2O gas (which is transparent) mixed with air usually almost instantly starts to condense into these water droplets. However, as with the example of clouds, steam is not necessary for these 'cloudy' water droplets to form.

In fact, in a shower, the airborne water droplets are probably forming after evaporation has occurred – something that is made more likely because of the hot water and moving air currents of a shower, but which also happens from a glass of water at room temperature.

You should take a look at the related question How does water evaporate if it doesn't boil for more information on this process.

  • $\begingroup$ If the fog that forms in a shower is not steam, then the white clouds that are emitted by an operating steam engine are not steam either because they are made of the same stuff. Sounds like you are using a strict technical definition of "steam" which basically is H2O gas, which is as transparent as air. The white puffy clouds of fog form almost instantly when hot H2O gas mixes with air. $\endgroup$ Commented Sep 16, 2015 at 18:59
  • $\begingroup$ @james_large Thank you. Those are good points, which I have added to my answer. $\endgroup$ Commented Sep 17, 2015 at 9:32

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