Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
I think April is ideal there. Out of four trips, three have been in mid-April. Weather (from an El Norte) cost us one day out of three weeks (over the 3 trips) of boat diving. So we did a shore dive instead. By the afternoon it was gone.
Water temps are around 79, hot and sunny pretty much everyday.
We are considering another trip there Apr 18-25, after the holiday vacations are over, as usual. The crowds are light, but not as quiet as it gets in say, September.
The upside to the thimble jellies is that turtles love to snack on them so when they're out, you'll usually see more turtles.scubawife is right about the thimble jellies. I think we have had them every trip in April. I have surfaced right in the middle of them a few times, but have never had a problem. I wear a full suit, but no hood.
Also, on two trips we saw numerous spawning sponges. That may have been at Columbia Reef, but I would have to check my log. Cool to see, although the viz is affected.
I can see then that I will probably end up bringing both of the 1/2 mm and the 3 mm.
82F is definitely 1/2 mm.
75F is definitely 3 mm.
And in between is always a roll of the dice.