I once did four day dives in Monterey in a wetsuit in February, at four different shore sites (and three the next day before heading home), so it's definitely doable. But it was the weekend after I got certified so I was highly motivated, I'd never been to most of them before, and my dives were typically shorter than now, say 30-35 minutes each.
Nowadays, diving dry, I usually do two or at most 3 longer and/or deeper dives a day, if at the same shore site. Partly that's due to it being more of a hassle to get in and out of my drysuit and pack everything away before moving to another site; leaving it on saves some time -- I'd always leave the wetsuit on. I also know a lot more divers now, so more time is consumed in conversation.
Three is easily possible (especially on a sunny day), assuming an early start and two dives before noon, followed by a long lunch SI and an afternoon dive (night optional). But you will almost certainly have to take a nap either before driving or else pulling over during the drive home; Betabel/Y Road was the point where my nodding off usually got dangerous. Diving Nitrox helps some people avoid this.
Guy