For future integration of a large number of qubits and complementary metal-oxide-semiconductor (CMOS) controllers, higher operation temperature of qubits is strongly desired. In this work, we fabricate p-channel silicon quantum dot (Si QD) devices on silicon-on-insulator for strong confinement of holes and investigate the temperature dependence of Coulomb oscillations and Coulomb diamonds. The physically defined Si QDs show clear Coulomb diamonds at temperatures up to 25 K, much higher than for gate defined QDs. To verify the temperature dependence of Coulomb diamonds, we carry out simulations and find good agreement with the experiment. The results suggest a possibility for realizing quantum computing chips with qubits integrated with CMOS electronics operating at higher temperature in the future.