The answer to 'why is my AC blowing cold air' is that there could be a few common causes. The most likely issue is a problem with the refrigerant level in your HVAC system. If the refrigerant is low, it can cause the air coming from your vents to feel colder than normal. This could be due to a refrigerant leak somewhere in the system.
Another possible cause is a malfunctioning thermostat or other electrical issue. If the thermostat is not properly regulating the temperature, it can lead to the AC blowing colder air than intended. In some cases, a problem with the compressor or other major component could also result in excessively cold air output.