The hold-up happened at the KNBT Bank on Freemansburg Avenue in Bethlehem Township around 10:30.
Moments later, a bystander reported seeing the woman changing her clothes in a car.
Police managed to apprehend her in the nearby Bethlehem Township Park.
The park was then evacuated and the Bethlehem Police Department's bomb squad called in to check out the woman's car.
A remote-controlled robot found no explosives, however police did remove a clown costume from the car.