To hear a whistle in your dream, denotes that you will be shocked by some sad intelligence, which will change your plans laid for innocent pleasure.
To dream that you are whistling, foretells a merry occasion in which you expect to figure largely. This dream for a young woman indicates indiscreet conduct and failure to obtain wishes is foretold.... Ten Thousand Dream Interpretation
In a dream, whistling represents pagan customs. Ifone hears a whistle or produces one in a dream, it may indicate an illness, or it could represent a vacant house or a ghost town.... Islamic Dream Interpretation