Answer
Critical temperature is the temperature above which the gas phase of a substance cannot be made to liquefy, no matter how large the applied pressure is.
Critical temperature of $CO_{2}$ is $31^{\circ}C$. In winter, the temperatures are below $31^{\circ}C$, so $CO_{2}$ will exist as a liquid and one can hear a sloshing sound when the extinguisher is gently shaken. But in summer, the temperatures are generally higher, so $CO_{2}$ won't exist as a liquid anymore no matter how much pressure is applied. It turns into gas and escapes the extinguisher. Hence, one cannot hear a sloshing sound in summer.
Work Step by Step
Critical temperature is the temperature above which the gas phase of a substance cannot be made to liquefy, no matter how large the applied pressure is.
Critical temperature of $CO_{2}$ is $31^{\circ}C$. In winter, the temperatures are below $31^{\circ}C$, so $CO_{2}$ will exist as a liquid and one can hear a sloshing sound when the extinguisher is gently shaken. But in summer, the temperatures are generally higher, so $CO_{2}$ won't exist as a liquid anymore no matter how much pressure is applied. It turns into gas and escapes the extinguisher. Hence, one cannot hear a sloshing sound in summer.
