The Big Dictionary of Dreams

by Martha Clarke
This dream could be a warning of your physical state: You may be cold and have a fever. But it could also signify that your temperature, metaphorically speaking, is too high; perhaps due to attraction that you feel for someone.

It is also possible that the presence of a thermometer in dreams reflects a concern with determining specific facts, or perhaps it alludes that you are trying to “take the temperature” of some new project or idea that you have in mind. On the other hand, you should not forget that the thermometer contains mercury, so it may be interesting to investigate the role of this god in Roman mythology or the influence of the planet in astrology.

Ten Thousand Dream Dictionary

by Pamela Ball
1- A thermometer in a dream will be representative of judging our warmth and feelings. We may be uncertain of how we come across to other people and need some kind of outside measurement.

A clinical thermometer would portray our emotional warmth, whereas an external thermometer would suggest our intellectual abilities.

2- Psychologically we sometimes need an external evaluation as to where we are coming from.

A thermometer would be a reassurance device.

3- Just as a thermometer measures temperature, the way we handle situations around us will give indications of our spiritual health and ability.

Strangest Dream Explanations

by Dream Explanations - Anonymous
If you dream of a thermometer then your body might be literally too hot or too cold. Also, a thermometer could signify degrees of separation between you and someone you love. Your dream might be showing you where you’ve gotten out of balance, and where it might be appropriate for you to heat things up in your life, or to take time to chill out.

See Hot or Cold.