A/C not working properly

Good morning,

My car has abnormal function. When I turn on my A/C for first time it blows cold air and monitor at 7 degrees Celsius, but when I switch off my A/C off for some time like go out from the car and buy something from groceries. When I switch on my A/C again it blows warm air. I've check my clutch and it was engage my compressor spinning.I monitor the pressure when it blowing cold was 35 low and 220 psi high at 100 degree F ambient temperature. Usually this is happening when temperature ambient at 45 degrees Celsius. When the car rest for three hours what I observe it will give cold air again when A/C turn on again. What could be the problem?