Source: The Great Interpretation of Dreams (Ibn Sirin)
(By analogy with fever and scales) A thermometer in a dream indicates anxiety and worry, or a test of one's condition. Its rise indicates hardship, and its fall indicates weakness.
Source: Perfuming Humanity in the Expression of Dreams (Al-Nabulsi)
(By analogy) A thermometer indicates a man who distinguishes between matters.
Source: Signs in the Science of Expressions (Ibn Shaheen)
(By analogy) A thermometer is interpreted as worry. Whoever sees himself using one is in worry and anxiety.