If you are getting cold, and unable to recover between dives then a drysuit is a good move.
I dive in the UK predominantly, you can use a wetsuit in the summer, BUT those that often do often end up skipping the second dive because their core temperature has dropped during the dive and they can't warm up between dives.
I have dived in California, in hire gear ( a wetsuit), and not found d it a problem. But, if I was based here I would probably use a drysuit, especially during the older months. It's not just the water temp that's an issue, it's the wind chill when you get out and the fact that you are using body temp to dry the wetsuit if you keep it on, and putting on a wet wetsuit is never enjoyable.
Drysuit diving is not as difficult as often stated. It's different, there is an adjustment. It is an easily mastered skill, like learning buoyancy control using a stab jacket (or wing). In many ways it's lazy diving, with cvd (constant volume dump), once set (and you have confidence in it), you never consciously dump air on ascent, the dump valve does that as the volume increases as the pressure (depth) decreases.
The only other consideration to consider is that you can get very warm in a dry suit on the surface if the ambient temp is high and / or you have strong direct sunlight. This can cause heat stroke, at worst, or heavy perspiration prior to entering the water that can have a 'chilling' effect on the body once you finally get in.
Also, on long dives, it is not desirable to relieve yourself in a dry suit, unless you are using a happy or pee valve ( which is more complicated fro women then men). The issue of relieving oneself in a dry suit does mean that people often fail to drink sufficient fluids due to this issue - not to be recommended.
I would give a drysuit a go, even if you purchase a secondhand one that leaks, you can learn a lot and gain confidence prior to investing in a good one. You do have the advantage that dui are just up the road in San Diego.
Gareth
