Systems and methods of determining settlement characteristics of a drilling mud are disclosed. Conditions under which heavier elements of the drilling mud settle under the influence of gravity can be determined. Samples of drilling mud can be placed in testing cells, and ultrasonic test pulses can be transmitted through the samples. Responses to the test pulses can be detected and compared to other responses detected at different vertical positions within the testing cell. Settlement can be detected when the responses from different vertical positions are generally dissimilar. An environmental temperature of the testing cell can be changed over a testing time interval, and a settlement temperature can be determined by detecting a divergence in the responses from different vertical positions.