In this paper, the influence of temperature variation on the characteristics and performance of flux-switching permanent magnet (FSPM) machines are analyzed and investigated. The flux linkage, torque output capability, and inductance variation as functions of the temperature are simulated and analyzed. The paper also shows the influence of temperature variation on key FSPM machines performance including constant torque curves, voltage limit ellipses, maximum torque per ampere curves, and torque-speed curves. The difference of temperature effects between FSPM machines and interior permanent magnet machines are also discussed. The results and trends shown in this paper set a foundation for developing control algorithm which takes the temperature effects into consideration, especially in the applications where operating temperature varies significantly.