Wave Heights by month in the Gulf of Mexico

Weather is always an issue when going offshore. The wind and resulting waves can make or break a Texas Pelagic trip. Because the Gulf of Mexico is a comparatively small basin compared to the Atlantic or Pacific Oceans the wave lengths in the Gulf are much shorter. Therefore a five foot wave in the Gulf has steeper sides than a 5 foot oceanic wave. This makes for a rougher boat ride given the same wave height than is typically experienced on either of North America’s ocean coasts.

The other factor for Texas Pelagics is the much greater distance we have to travel to reach pelagic depth waters. From South Padre Island this is about 50 miles or roughly a 4 hour one way travel time. Rougher seas mean slower travel speeds which can make reaching deep waters a problem for a 12 hour trip.

Last year I downloaded wave height data for 15 years from 2000 to 2014 for the NOAA National Buoy Data Base for Buoy 42020, the closest wave height recording buoy to South Padre Island.

From this data I was able to graph the wave heights recorded for this whole time period. These yearly wave height graphs clearly illustrate what any Gulf mariner of fisherman surely already knows, the seas can be very rough in the winter and very calm in the summer on average.

Our Pelagic experience has taught us that with seas greater than 5 feet it is not possible to run a viable Texas Pelagic because it would prevent us from reaching deep pelagic waters for the reasons I’ve already mentioned above.

I have always wondered what are the odds of getting blown out on a Texas Pelagic? Well now I have developed the statistics from these 15 years of wave height data to finally answer that question. The two graphs below illustrate the answers to that question.

Percentage Wave Heights Buoy40020

This first graph shows the percentage of wave height readings from Buoy 42020 that were greater than 5 feet. The data I have is at one hour increments for 24/7/365. There are some data gaps resulting from buoy downtime. I averaged the data over one month time periods and plotted each year individually illustrated as the dots. Then I took an average of all years for each month and plotted that as the red line

Cleary August is the calmest month with wave heights greater than 5 feet occurring less than 10% of the time in all years and on average about only 5% of the time. This is why I scheduled 2 trips for August.

July is the second calmest month averaging 12%. June is third at 17%; September fourth at 19%.

October fifth at 31%. The remaining months are all greater so the odds of having a successful Texas Pelagic are less than 60% on average in the remaining months. Of course this doesn’t really help us predict any one day in the future, but it gives us the odds. So if you want a calm day offshore your most likely to find it in August, although dead calm seas can occur in any month.

Average Wave Heights Buoy40020
The second graph uses the same raw data but now it’s plotted as average wave height for all data points in each month. It still shows that August has the calmest seas averaging 2.7 feet.


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