The invention relates to a precision scale with a scale chamber (16), a windshield (18, 20, 22) which surrounds the scale chamber (16), an air conditioning module (34) which is removably arranged in the scale chamber (16), a processor (32) which is arranged in the precision scale, a data input unit which is arranged on the precision scale, and a data transmission path with which data can be exchanged between the air conditioning module (34) and the processor (32), said processor (32) containing a measurement uncertainty detection module (33) with which the measurement uncertainty of the scale can be ascertained. The invention also relates to an air conditioning module for electrically coupling to a precision scale in a removable manner, said air conditioning module (34) forming a sealed unit and having an air pressure sensor (62), a humidity sensor (54), an air temperature sensor (52), and a part of a data transmission path via which data can be transmitted to a processor outside of the air conditioning module. The invention finally relates to a method for determining the measurement uncertainty of a precision scale comprising a scale chamber (16) which is separated from the surroundings by a windshield and in which an air pressure sensor (62), a humidity sensor (54), and an air temperature sensor (52) are arranged, said sensors (52, 54, 62) being coupled to a processor (32). Goods to be weighed, in the form of a test object, are weighed, and the following steps are carried out: - ascertaining the air pressure, the humidity, and the air temperature in the scale chamber (16) using the sensors (52, 54, 62); - weighing the test object; - determining the standard uncertainty of the weighing method; - determining the standard uncertainty of the mass of the test object; and - ascertaining a total uncertainty of the scale result.