5030's are notorious for weak ac output when the ambient temperatures are high. I know, I had one. A good solution is to shroud the space between the condensor and the front of the radiator with rubber strips attached to the framework. That allows more air flow through the condensor, something that the stock confoguration lacks. Adding a layer of foil bubble foil insulation to the top of the underside of the cab roof also helps. There is no insulation on the underside of the cab roof and the sun significantly heats the orange plastic, making a marginal ac work all the harder.
You also need to be keeping the nets clean and the radiator and condensor blown out and clean, like in more than once per day.
Improving airflow through the condensor, keeping the heat exchangers clean and some overhead insulation will go a long way toward keeping you cool on the hottest days.