Capacitively shunted microelectromechanical (MEM) switches were designed, fabricated and tested in an earlier work. The switch is composed of a coplanar waveguide (CPW) structure with an Au bridge membrane suspended above a center conductor covered with a BaTiO3 dielectric. The membrane is actuated by electrostatic force acting between the center conductor of the CPW and the membrane when a voltage is applied. We have noted that pull-down voltages for MEM switches always demonstrate an extremely strong temperature dependence when actuated at cryogenic temperature. This paper improves the pull-down voltage prediction of MEM switches at cryogenic temperature using the mechanical properties of the bridge, thin film and substrate materials used in the switch. The theoretical and experimental results of the actuation voltages of these structures as a function of temperature are presented and compared. © 2008 IEEE.