Looking at
California Frogs and Toads the only options seem to be Chorus Frogs. The California treefrog doesn't have the dark mask behind the eye so it's one of the other three.
According to the description of any of the other three,
Pseudacris hypochondriaca hypochondriaca - Baja California Treefrog, they used to be listed as one species before being split into three. In other words, you will likely have little to no chance of telling them apart. The range maps given may help, but if you're near an edge or where they overlap this is probably very unreliable.
On the plus side it doesn't matter for their care, and they're often still all collectively called "Pacific chorus frogs". There are a few members here who keep Pacific chorus frogs who will hopefully help out and and here's a care sheet to get you started
Frog Forum - Pacific Chorus Frog