I grew up on South Padre Island and spent my childhood snorkeling both the North Jetties (Port Mansfield) and the South Jetties (SPI/Boca Chica). Chairman is spot on about not being able to plan for blue water. It is really one of those things where we locals monitor it daily and when conditions are just right we drop everything and go. Sometimes the window of opportunity is merely a few hours before the tide shifts and it goes bad. Some years we have weeks straight of "good" visibility, which for the jetties down here ranges between 6-25ft, other years we have nothing. If conditions are just right there are some nice areas around our rocky jetties to dive with interesting marine life including a lot of tropical species during the summer.
On September 20th of 2012 a Norther blew through and while the beach side of the South Padre Island jetties was a dirty, brown mess, the opposite jetties (on Boca Chica Beach) provided a nice wind break. The highest tide was in the evening so I suggested to a friend we make a run out for a night dive. I knew full well visibility may be zero but we went for it anyways and were pleasantly surprised with a 10+ft viz. We were down for about an hour and a half with a maximum depth of 26 ft (much shallower than the North jetties). We dove the entire length starting from just beyond the shore. It was a really great dive with octopus, squid, telesto corals, electric rays, scorpionfish, and all manner of other fish etc... There was a lot of particulate matter in the water column but we could see fine (as far as our lights would illuminate anyways) and had a really great experience. But again, it is one of those things you can't plan... you have to be in the right place at precisely the right time so it really helps to "live" in these areas.
LOL
