For the first time, both pull-in and release transients were characterized under high RF power levels on electrostatically actuated capacitive switches that exhibited little ambient temperature dependence under small-signal conditions. In spite of the complication of buckling, thermal resistances and time constants were extracted for both pulled-in and released states. In the pulled-in state, the extracted thermal resistance and time constant were approximately 5000°C/W and 40μs, respectively. In the released state, the corresponding values were approximately 3000°C/W and 100μs, respectively. These extracted parameters could serve as the foundation for physical understanding, as well as compact modeling of large-signal transients. They could also help improve the design of switches that are more robust against temperature change and RF loading.