Police were called to the Home Depot store shortly before noon about a baby, alone and crying in a car seat, inside a car in the parking lot.
The windows were partially down, but temperatures neared 90°.
Officers say they were about to break into the car when the father, identified as 32-year-old Tyrel Rawlins, came out of the store.
The infant was sweaty but not hurt.
Police say an investigation determined Rawlins had been inside the store for about 13-minutes.
They said the internal temperature of the car was at least 99°.