At about 3.5 cm long, I thought this was a juvenile green tree frog, but upon getting a better look at the photo (this individual was hiding under an informational sign and was difficult to see without the camera), I am pretty sure this is a squirrel tree frog (Hyla squirrella).
Most tree frogs seem to come in a variety of colors, and some can even change color, to an extent, to match their background, so identifying them can be a little tricky. Here’s an excellent resource (not incidentally, the one I used) for telling green tree frogs and squirrel tree frogs apart.
Squirrel tree frogs eat ants, beetles, crickets, spiders, termites, and other small critters they can fit in their mouths. They breed March through August, and live all over the southeast United States.
Squirrel tree frogs are sometimes known as rain frogs because they can often be heard calling during and after rain showers. The call sounds like a squirrel chattering, hence the name “squirrel tree frog”. You can hear their call by visiting the USGS Frog Call Lookup and entering the name of the frog you want to hear.