Islamic Interpretation of Dreams (Ibn-i Sirin):
In a dream, vapor represents a symptom of cataract that makes one’s eye cloudy and obscures his sight.
If during the summer one sees vapor exhaling from his mouth in a dream, which is a common phenomena in cold weather, it means an internal disease, or exposing one’s secrets.
If the person in question in such a dream is a believer on the path, he may become heedless.
Ifhe is a man of knowledge, he may invent a provoking trend. On the other hand, vapor in a dream may imply falsehood, lies and idle talk.
(Also see Clouds)