Races›Ironman 140.6

IRONMAN JACKSONVILLE

Race-specific weather data and nutrition strategy for IRONMAN JACKSONVILLE in Jacksonville, FL, US.

TriathlonFull Ironman (140.6 mi)Registration Open
LocationJacksonville, FL, US
Date
May 21, 2026
RegisterBuild Your Fueling PlanOfficial website
Race Location30.33°, -81.66°
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Race-Day Conditions

High Heat Risk
Temperature
87°F

79–95°F range

Humidity
76%

63–85% range

5-year average via Open-Meteo. 80% of race days fall within the range shown. Updated Mar 30, 2026.

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High heat risk

Race-day temperatures can reach 95°F. Expect 15-25% higher sweat rates. Increase sodium to 800-1200 mg/hr and plan for more frequent fluid intake. Pre-cool with ice and cold fluids.

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High humidity conditions

Humidity averaging 76% combined with warm temperatures impairs sweat evaporation. Your body works harder to cool itself. Reduce intensity expectations and increase fluid intake.

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Gut fatigue management

For races lasting 6+ hours, gut absorption efficiency decreases over time. Plan to reduce carb intake by 10-15% after hour 6 and shift toward easily digestible sources like gels and simple sugars.

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Segment transitions matter

Fueling needs differ across swim, bike, and run. The bike is your best opportunity for calorie intake — aim to consume 60-80% of total nutrition on the bike. Reduce volume entering T2 to avoid GI distress on the run.

Sample Ironman 140.6 Nutrition Plan

Based on a 155 lb triathlete finishing in ~12 hours. Your plan will differ based on body weight, experience, and conditions.

HourCarbsFluidSodiumExample
Swim0g0oz0mgNo fueling during swim
Bike 170g29oz600mgDrink mix + gel
Bike 280g29oz600mgDrink mix + bar
Bike 380g29oz600mgDrink mix + gel
Bike 480g29oz600mgDrink mix + chews
Bike 570g26oz500mgDrink mix + gel
Run 160g19oz500mg2 gels + water
Run 255g19oz500mgGel + cola
Run 350g17oz400mgGel + sports drink
Total545g197oz4300mg

These are general estimates. Get your personalized plan for this race →

What to Expect at IRONMAN JACKSONVILLE

IRONMAN JACKSONVILLE is a Full Ironman (140.6 mi) ironman 140.6 held in Jacksonville, FL, US. Based on 5 years of historical weather data, athletes can expect median race-day temperatures around 87°F.

Temperatures at IRONMAN JACKSONVILLE typically range from 79°F to 95°F. This puts the race squarely in high heat risk territory. Sweat rates can increase 15–25% in these conditions, meaning both fluid and sodium demands rise significantly. Athletes should plan for increased hydration, consider pre-cooling strategies, and expect pace adjustments — even well-trained runners slow 1–3% per 10°F above 60°F. Humidity is also a factor here, with levels reaching 85% on warmer days. High humidity impairs sweat evaporation — your body's primary cooling mechanism — so perceived effort rises even when temperatures look manageable on paper.

For a full-distance Ironman, nutrition is often the fourth discipline. The bike leg is your primary fueling window — aim to consume 60–80% of total calories there, when the gut handles volume best. Transition to simpler, faster-absorbing fuels on the run as GI tolerance drops. With 10–17 hours of racing, even small hourly deficits compound dramatically by the finish.

We do our best to keep race details accurate and up to date, but things can change and occasionally we simply get something wrong.

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Fueling and hydration suggestions are based on published sports science research including ACSM position stands, ISSN guidelines, and peer-reviewed work by Jeukendrup, Sawka, and others. This is not medical or dietary advice — individual needs vary. Always test your nutrition strategy in training before race day.

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Frequently Asked Questions

What should I eat during the race?
Your nutrition plan depends on your body weight, experience level, and race-day conditions. Use our free calculator to get a personalized, hour-by-hour fueling plan with specific carb, fluid, and sodium targets for this Ironman 140.6.
What is the typical race-day weather?
Based on 5 years of historical data, race-day temperatures at Jacksonville, FL typically range from 79°F to 95°F (median 87°F). Humidity ranges from 63% to 85%.
How much water should I drink?
Fluid needs vary based on your sweat rate, body weight, and race-day temperature. A typical range is 400-800 mL per hour, but hotter conditions at Jacksonville, FL may require more. Our calculator provides personalized fluid targets adjusted for the expected weather.
How many calories do I need?
Rather than replacing all calories burned, focus on carbohydrate intake — the primary fuel for endurance performance. Target 30-50% of caloric expenditure through carbs. Our calculator computes the exact hourly targets based on your Ironman 140.6 pace and body weight.
When should I start fueling?
Begin fueling within the first 30-45 minutes. Start at about 70% of your target intake and ramp up to full by hour 2. This gives your gut time to adjust. Starting too late makes it nearly impossible to catch up on carbs and fluids.
Source: runsignup_playtriView sourceVerified: Mar 30, 2026Confidence: 85%