It depends on what type of Hydrangea it is. Is this a Hydrangea that was given to you as a gift from a florist? If so, it may not survive outside. Some of these types of plants are "specialty" plants and don't usually survive outside.

Although you live in a generally warmer climate, you can try growing it outside if you wait til the weather warms up a bit more and the ground warms up. Plant it in an area that is well drained, but not dry, and will get some sun in the morning, but not the hot afternoon sun.

Or just repot it and keep it as a houseplant.