To dream of a thermometer represents your feelings about how positive or negative a situation is. An emotional gauge as to how good or bad something is. Attempting to feel how good or bad a choice you are considering is. Gauging or determining people’s emotional state. Determining whether or not conditions are right for your ideas or goals.
Heat reflects negativity or the degree of emotional danger a situation holds. Cold reflects positivity or the degree of emotional safety a situation holds. Cold temperatures may also reflect how insensitive people, situations, or choices feel.
Alternatively, a thermometer may also symbolize a barometer of your mood.
Example: A woman dreamed of a baby thermometer. In waking life she was trying to determine whether or not it was a good idea to keep her baby once she learned of her conception