The FLIR One can measure temperatures from -20 °C to 120 °C (-4 °F to 248 °F) so it should be able to measure negative temperatures up to -20 °C. For accurate temperature readings, the maximum distance is about 50 yards in perfect atmospheric conditions (no rain, clouds or humidity). The detection passed 50 yards may not be accurate, however, you may still manage to detect some heat signatures which would tell you if the object is warmer or colder relative to its surroundings.
Please keep in mind emissivity of the objects will affect temperature readings as well as gain mode if you have a Pro model.
This reply was modified 1 year, 11 months ago by Allison.
Thermal cameras, like visible cameras can see as far as your eye can see in most cases. Whether you will “see something” at a given distance depends on the size of the size of the object and the contrast walgreenslistens.