Mouillé vs. humide vs. trempe

In the French language, 'mouillé', 'humide' and 'trempé' are three adjectives commonly used to describe different degrees and contexts of wetness. Each has its own nuances and situations in which it is most appropriate.

Mouillé

'Mouillé' refers to something that is wet or damp, often slightly or just having been in contact with liquid.
J'ai les pieds mouillés après avoir marché dans l'herbe.
(My feet are wet after walking on the grass.)
Il a les cheveux mouillés car il vient de prendre sa douche.
(His hair is wet because he just took a shower.)

Humide

'Humide' describes a state of being moist or damp, and it's often used for air quality or surfaces that are not directly soaked but have a higher level of moisture.
L'air est très humide aujourd'hui, c'est difficile de respirer.
(The air is very humid today, it's hard to breathe.)
Cette serviette est encore humide; elle n'a pas bien séché.
(This towel is still damp; it didn't dry well.)

Trempé

'Trempé' implies that something is soaked or drenched, indicating that it has absorbed a lot of liquid, much more than merely 'mouillé' or 'humide'.
Après la pluie torrentielle, il était complètement trempé.
(After the torrential rain, he was completely soaked.)
J'ai laissé mes vêtements sous la pluie, et maintenant ils sont tous trempés.
(I left my clothes out in the rain, and now they are all drenched.)

Summary

'Mouillé', 'humide' and 'trempé' offer nuanced ways of describing wetness in French. 'Mouillé' suggests a slight wetness or dampness, often from direct contact with a liquid. 'Humide' refers to moisture in the air or on surfaces, suggesting a state of dampness rather than wetness. 'Trempé' indicates a condition of being thoroughly soaked or drenched. Understanding these differences will help you to accurately describe different states of wetness.