IRONMAN 70.3 Chattanooga
Course breakdown, historical weather, and field analysis.
The scenic gem of the American South — river, ridges, and riverwalk
Chattanooga, United States · May 17, 2026
IRONMAN 70.3 Chattanooga is set in one of the most beautiful small cities in the American South. A downstream river swim in the Tennessee River, a challenging bike through the ridges and valleys outside the city, and a flat run along the Chattanooga riverwalk. The natural beauty and genuine Southern hospitality make this a favourite among US athletes.
- Swim
- 2.4 km
- River
- Bike
- 91.3 km
- ↑667m · Rolling
- Run
- 21.2 km
- ↑239m · Rolling
- Air Temp
- 16–32°C
- Water Temp
- 23°C
- Wind
- 11 km/h
- SE
Swim Course
Downstream swim in the Tennessee River
The swim takes place in the Tennessee River with a downstream current assist. This is one of the faster 70.3 swims on the circuit — the current carries athletes downstream, producing swim splits that are significantly faster than pool-equivalent pace. Water temperatures in May are typically 18–22°C and wetsuit-legal. The river conditions are calm with no waves, though the current means sighting is important to avoid drifting off course.
- Downstream current produces fast swim splits
- Calm river conditions — no waves or swell
- Wetsuit-legal at 18–22°C
- Sighting is critical to stay on the racing line
Bike Course
Ridge and valley riding through the Tennessee countryside
The bike course leaves the flat river valley and heads into the ridges and valleys of the surrounding Tennessee countryside. This is a rolling to hilly course with genuine climbing — a significant contrast to the flat Florida races. The roads wind through beautiful rural scenery with a mix of short punchy climbs and longer sustained efforts. Athletes who can manage their power on the climbs and recover efficiently on the descents will thrive here.
- Rolling to hilly terrain through Tennessee ridges
- Genuine climbing — not a flat time trial
- Beautiful rural roads through the countryside
- Power management on climbs is key to a good bike split
Run Course
Flat riverwalk run through downtown Chattanooga
The run course follows the Chattanooga riverwalk along the Tennessee River and through the city centre. The terrain is flat and fast, providing relief after the hilly bike. The downtown setting offers strong spectator support, and the riverwalk provides a pleasant, shaded running environment. Chattanooga's Southern charm comes through in the crowd support — this is a community that genuinely embraces race day.
- Flat riverwalk course — welcome relief after the hilly bike
- Downtown Chattanooga with strong community support
- Partial shade along the riverwalk sections
- Southern hospitality makes for a memorable race atmosphere
Race Day Conditions
Warm Southern spring — pleasant with potential for heat
May in Chattanooga brings warm spring conditions. Air temperatures range from 15–28°C, warm enough to be comfortable but with potential for heat in the afternoon run. Humidity can be moderate to high. The river valley location means still air in the morning with potential afternoon breezes. Overall, the conditions are manageable — significantly more comfortable than the Florida or Texas heat races.
Race Field Insights
How the Field Performs
Aggregated from 13,324 finishers (2021–2025)
- Total Starters
- 14,044
- Finishers
- 13,324
- DNF Rate
- 4.9%
- Years of Data
- 2021–2025
- Median Finish
- 6h 01m
Finish Time Distribution
How the Median Finisher Spends Race Day
What Each Pace Looks Like
Fast | Solid | Median | Back of Pack | Slow (P90) | |
|---|---|---|---|---|---|
| Swim | 31m 24s | 34m 27s | 37m 56s | 42m 02s | 46m 50s |
| Bike | 2h 31m | 2h 43m | 2h 58m | 3h 16m | 3h 34m |
| Run | 1h 42m | 1h 57m | 2h 17m | 2h 41m | 3h 03m |
| Finish | 4h 44m | 5h 19m | 6h 01m | 6h 48m | 7h 30m |
Related reading
Race Day Weather and What It's Really Doing to Your Pacing Plan
Performance starts dropping over 22°C and humidity makes it worse. How heat compounds across the bike and run — and why the bike hides it.
Read postYour Race Plan Isn't Generic — Why Course Intelligence Changes Everything
Same FTP on two different courses produces two completely different races. Elevation, wind, and shelter change what every watt is worth.
Read postPlan IRONMAN 70.3 Chattanooga with Keiro
Get a complete pacing strategy for every discipline — built from this course, forecast weather, and your fitness.
Independent analysis. KeiroLabs is not the event organizer and is not affiliated with the race organizer.