The answer to 'why is my thermostat blowing cold air' is that there may be an issue with your HVAC system's cooling function. This could be caused by a problem with the compressor, refrigerant levels, or the thermostat itself. Common symptoms include the system running continuously, but only blowing cold air, or the air not feeling as cool as it should.
Some potential solutions include checking the thermostat settings, inspecting the air filters, and ensuring the outdoor condenser unit is clear of debris. However, if the issue persists, it's best to call in a professional HVAC technician to diagnose and repair the problem. Attempting DIY repairs on an HVAC system can be dangerous and may end up causing further damage.