Article: Calla Lilies will survive outdoors over winter in mild climates that don't experience much sustained snow, deep freezes and heavy prolonged rainfall in the colder months. They can generally cope outdoors through winter in zones 8 through 10. This means that they can survive in temperatures that do not drop below 30 to 35 degrees F (-1.1 to 1.7 degrees C). After flowering has ended, refrain from watering and allow the plant to die back. Try to refrain from cutting the foliage until it has withered away. If you are overwintering outdoors, apply a mulch of about four inches of straw or evergreen branches. You can also put them under an upturned pot or cloche. Do this in the fall before the ground gets cold.

What is a summary?
Consider keeping your Callas outside if you live in a mild climate. Help your plant to die back. Give your Callas some protection.