a /c issue 2013 KIA optima

What is your question?

a/c works fine when driving if your at idle or in slow moving traffic the a/c starts blowing not as cool to warm air.When the car is parked in the sun it takes awhile to overcome the heat build up in the car. what could be causing this issue .

What makes this problem better or worse?

driving at normal speeds makes it better

How long has your 2013 Kia Optima had this problem?

noticeable about a month