Planning with seasons, tides and weather  
and what to consider.   

Diving in the Texas Gulf is a year round activity. Understanding the changes in the seasons allows divers to realize that the water temperature hardly drops below 68 degrees in the main diving range of 30 ft to 80 ft for rigs that are 20 miles off shore. The Earth axes and the angle of the moon does play a role in stronger currents, changes in the back flow of the Mississippi River along the coast adding to a higher sediment in the water. Then Comes the weather which the surface swells and waves change according to the direction and strength of the air movement. Planning a dive in the gulf is a process of considering what is the best days for diving and what to watch out for.

Considerations:

1) Direction of wind: Most wind from the southeast and southwest result in calm seas. Winds from the North usually result in large choppy swells, stronger the wind, higher the swells and waves start appearing. During January through April the predominate winds are from the North or Northwest, 65% of the days. This still means that 35% of those 4 months have good diving days. Watch the weather for cold fronts and when they might arrive. Next winds from the south are usually warmer air and push the colder water in close to shore. That is why beach water temp is a good reflection of surface water temperature out to about 10 miles. However if a cold blast of cold air stays for 5 days or longer the off shore water temperature drops till you get about 70 mile offshore and effects the long term coldness of the water warming in the early summer. Some years in March I have had surface water temp at 72 degrees and descending got warmer after 35 feet then at 70 feet had a drastic change of water temp to 56 degrees. Yet when Houston has mild winters with only short term of two or three days of winter blast, I have found bottom temps as high as 72 degrees at 100 feet on the same rig. Each year the water temperature is controlled by winter blast and the duration they last. Next Watch the timing of weather fronts to be prepared for rainy days and change in exposure suits.

2) Currents off-shore: Texas has the benefit of having the Gulf Stream pushing the water to the East. Where most of the Earths ocean currents flow to the West. This means waters offshore are mostly warm waters from the tropics. (Note: they carry all the zoo plankton from the Tropics.) This pushes the waters along the South Texas region northward and keeps the warmer water flowing toward the Northeast.

To understand the currents at off-shore dive sites one must consider the dominate current, wind direction and tidal affects on the water pooled in the Gulf of Mexico. First there are usually three different currents flowing at different speeds in the water column off-shore. (Dive Sites between 20 mile to 50 miles.) There is the surface current created by the wind which usually is within the first 15 to 20 feet of the surface. The days before and after a full moon will increase the currents in this zone. The second zone of currents is usually mild except after storms with lots of rain and high winds, near the full moon and the spring tide change due to earths rotation on its axes. The last zone is mostly effected by strong winds and the daily tidal amount of water movement. For the best water visibility and least amount of current in all three zones is when your in day 16 of the moons rotation where the least amount of tidal water is exchanged, and when the winds are out of the south-southeast for five days straight.