Air conditioning and climate control systems need periodic maintenance. In particular, they use a type of cooling similar to that of a standard domestic fridge but due to the nature of how they are used in cars, the coolant used can degrade over time and need renewing.
This is referred to as ‘recharging’ the air conditioning, and is something that can only legally be done by certified and approved operators. It is not a job for the home mechanic.
The average time to complete a recharge is around 1hr, so it can be done whilst you wait.