Why do the pendulum clocks go slow in summer and fast in winter?

Why do the pendulum clock run slow in summer and fast in winter?

Pendulum clocks may run slow in summer and fast in winter .Why?

Statement-1 : Pendulum clocks go slow in summer and fast in winter. Statement-2 : The length of the pendulum used in clock increases in summer.

Statement-1 : Pendulum clocks go slow in summer and fast in winter. Statement-2 : The length of the pendulum used in clock increases in summer.

Statement-1 : Pendulum clocks go slow in summer and fast in winter. Statement-2 : The length of the pendulum used in clock increases in summer.

Why do pendulum clocks made of ordinary metal go slow in summer ?