My bugeye has an electric fan. It was installed by the PO who lived in the desert near Sacramento. He had it wired so it was always on, and living there, I don't doubt that he needed it on continuously.
I now have it on a thermostat, so it only comes on around 190F. With the fan running continuously, the car was slow to warm up on cool days. The cooling system is in good shape and really doesn't need the fan, except when I'm stuck in traffic on hot days. It almost never comes on.
I wouldn't bother unless you're convinced you need it. Are you having trouble with overheating? In Fresno, in summer, I can imagine that it could be a help. If you get one, be sure it is as large as possible, covering the full width of the radiator (or full height if that dimension is smaller). Simplest thing is to mount it on the front of the engine and wire it through a switch. Then, you can just flick it on when needed.
Of course, don't expect a fan to compensate for a cooling system in poor shape. Be sure that it is clean, radiator is good, and so on.