I just did the Coronodos Island trip in mid-August. It is a little over an hour to get there via boat and it was quite surgey that day (one unfortunate soul was chumming the entire trip). Water temps had dropped from the prior week (when they were pushing 70) and it was 53 at depth.
We didn't do any deep dives, but I am not sure that a beginner would feel comfortable with all the surge as it pushed me around quite a bit and at one point I felt like I was struggling in a losing battle -- conditions change, but just wanted you to be aware of that. The day we went we saw tons of Garibaldi and rock fish and urchins, and not much else.
The dive op, Blue Escape, is a good one. The captain and DM were great -- just remember, the dives are on your own, so you'd best be up on your navigation skills. As an aside, the hot soup was delicious and the fresh brownies a nice surprise treat!
You may also wish to check out diver.net/bbs. There is a listing there of most dive ops and boats in southern Cal. Plus, you can post questions for people who dive there routinely.
Enjoy,
Margaret
Counting the days to return to Saba
(Oct. 30 - Nov. 8)