What is the accuracy of the humidity sensor?

The Tive trackers measure the relative humidity (RH) which is the amount of moisture in the air compared to what the air can "hold" at that temperature. The devices use a digital humidity sensor which operates with a similar principle as the wet- and dry-bulb hygrometer. A relative humidity measurement of 100% means that the air is holding as much moisture as it can at a given temperature, in the form of water vapor. 
The devices can measure relative humidity with a typical accuracy of ±2 %RH and a maximum tolerance of ±4.5 %RH between the range of 10 to 90% RH. The typical accuracy increases to ±4 %RH when relative humidity is above 90% RH and below 10% RH. Below is a diagram showing the maximal and typical tolerance of RH @ 25°C.

The resolution of the humidity measurement is 0.1 % RH