The ideal AC vent temperature shouldn’t exceed the 40 Degrees Fahrenheit limit. Higher than 42 degrees is a concerning matter for every car owner. However, the right discharge center vent temperature depends on the relative humidity (RH) and ambient air temperature. According to Auto AC Repair, suppose the air ambient temperature is between 77℉ and 95℉ and the humidity is between 50 and 60%. Then, the air temp at the ac vent should be 50℉ to 70℉.