Drysuits completely prevent the water coming inside the suits and stop the body temperature drop by giving an air space between suit and body, and protect from cold weather after on the surface or out of water becuase your body is not wet. However, because the air spaces get expanded and compressed at different depths in water, you need to pay extra attention to not only BCD but also drysuits by controlling the air amounts of both. In a drysuit, there are an inflator valve on the chest and an exhaust value on the left arm to control the air amount. It will be unfamiliar to most of divers who are used to wetsuits. Therefore, you need proper education to choose and use the right-fit drysuits to do good drysuit diving. Furthermore, you need proper instruction (wear/take off), constant care, and services for the suits as their waterproof condition is very crucial.
In California, you can enjoy diving regardless of weather, but the water temperature decreases as you go up north. Plus, you will feel colder when you are out of water in wet suits.
If you feel cold easily and hate coldness, wear drysuits. Then, diving will be more enjoyable.