There are stories about clothes freezing and drying in cold weather. The typical reason given for that is that the water is undergoing sublimation (ice -> vapor).

The phase diagram for water is

enter image description here

In a typical case, one would hang wet clothes outside, at say -5°C (or whatever realistic temperature). This would cause the clothes to freeze and then, in order to move between phases, the pressure would need to drop.

Note that this is the scenario I have in mind, not a direct water -> vapor transition (the usual kind, but also the one where the stating point on the graph is on liquid phase, and the ending point (external temp + current pressure) - in vapor phase).

Aren't the conditions a bit too esoteric for that to happen, often enough to have made it into some family legends?


2 Answers 2


I guess all you need for ice sublimation is low water vapor pressure (low humidity), not low atmospheric pressure.

  • $\begingroup$ Which is, of course, also true for evaporation of liquid water at 1 atm. $\endgroup$ Commented Jan 19 at 17:27

Phase diagrams are only describing phases of pure bodies. In the case of drying clothes, you have to take evaporation in account which depends on water partial pressure in the air as well as other factors like temperature and air flow.

Depending on the situation, ice evaporation can indeed happen and you could dry clothes during dry but freezing weather.

A bit more info here.


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