Duke 1/2 Water Temperature Prediction

I need a T-shirt that says “Triathlon Nerd”. I always think of really geeky ideas for my training.

Today I did a short open water swim workout at Jordan Lake. I brought my wetsuit and planned to swim two laps of the cove, one with and one without the suit. I wanted to compare how wearing the wetsuit affected how I deal with choppiness. It wasn’t very choppy, unfortunately. It was still a good workout. And, the wetsuit definitely made swimming in the little bit of chop easier!

Here’s a photo of the lake today:

Here’s the geeky part

I brought my digital meat thermometer to test the water temperature. It’s precise within 0.5 degrees. I stuck it into a big ziploc bag, and sucked all the air out before zipping it closed.

Before leaving home, I looked up the USAT rules for how they measure the temperature.

4.6 Measuring Water Temperature.

It is recommended, but not required that the water temperature for a race be finally determined by a measurement made within 2 hours of the race start. Measurements should be made in at least three locations on the swim course, spaced so as to divide the entire swim course into approximately equidistant segments, and measured at a depth of 18 inches below the surface of the water, at points where direct sunlight can strike the water. The water temperature for the race should be determined by averaging the three temperature measurements taken. A water temperature measurement should also be taken prior to any pre-race meetings in order to forecast to the athletes as early as possible the likely water temperature on race day and the likelihood of whether wet suits will be allowed on race day.

Once at the lake, I took my thermometer and swam around to test the temperature at different spots, at about 18″ deep like the USAT rules. The reading near the shoreline was 80 degrees. I swam out about 25 yards and took some more readings. Most of them ranged from 78.4 to 79 degrees, most were above 78.5. I assume they round up…? The lowest I got was when I was the farthest out, and stuck the thermometer into the water as deep as possible (more than 18″). That reading was 77.9 deg.

My Prediction for Duke Half Water Temperature

My prediction for this year’s Duke 1/2 is no wetsuit. Bring your wetsuit, but be mentally prepared to not use it. You can then rejoice if I am wrong! My prediction is based on:

1. The above temperature readings (obviously!)
2. It’s going to be sunny and 90 degrees tomorrow, giving a whole day for heating the water up a bit more
3. The US army corps website water reading for Tues said 76, and Thurs it says 77. And it hasn’t even been very hot this week (the heat wave started today)!

This blog was written Friday at 5pm. The US army corps website is showing Thursday’s reading of 77 deg. So far, Setup Events has not posted their pre-race reading.

Well, that’s it. Good luck to everyone doing the Duke 1/2.

Update: as of 10 pm, Setup still has not posted the pre-race water temp reading.

Update: as of 2 pm Saturday, Setup still has not posted the pre-race water temp reading. Unless I’m missing it on their site…? I’m looking at the NCTS page and the Duke 1/2 page, under News. Also, the Army corps page still shows Thurs temp reading.