Races›Ultra 100 Mile

Leadville Trail 100

Leadville Trail 100 is Aug 21, 2027 in Leadville. Build your free hour-by-hour plan.

RunningUltra 100 MileLottery
LocationLeadville, Colorado, US
Date
August 21, 2027
Build Your Fueling PlanOfficial website
Race Location39.25°, -106.29°
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Race-Day Conditions

Low Heat Risk
Temperature
68°F

60–73°F range

Humidity
65%

50–81% range

5-year average via Open-Meteo. 80% of race days fall within the range shown. Updated Nov 6, 2026.

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Favorable temperature range

Typical race-day temperature of 68°F is in the optimal range for performance. Standard fueling and hydration targets apply.

Sample Ultra 100 Mile Nutrition Plan

Based on a 155 lb runner finishing in ~24 hours. Your plan will differ based on body weight, experience, and conditions.

HourCarbsFluidSodiumExample
Hours 1–6360g100oz3000mgGels, chews, drink mix
Hours 7–12300g96oz3000mgReal food rotation + gels
Hours 13–18240g84oz2400mgBroth, potatoes, cola, gels
Hours 19–24200g72oz2000mgWhatever works + caffeine
Total1100g352oz10400mg

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

What to Expect at Leadville Trail 100

Leadville Trail 100 is a 100-mile ultra held in Leadville, Colorado, US. Based on 5 years of historical weather data, athletes can expect median race-day temperatures around 68°F.

Temperatures at Leadville Trail 100 typically range from 60°F to 73°F. This falls in the favorable range for endurance performance. Standard fueling and hydration targets should work well, though individual sweat rates still vary — a sweat test gives the most accurate picture. Humidity is also a factor here, with levels reaching 81% 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.

Ultra-distance racing demands a flexible nutrition strategy. Gut absorption efficiency declines over many hours, so plan for variety — alternating between gels, chews, real food, and liquids helps prevent flavor fatigue and GI rebellion. Many ultra runners find that what works at hour 3 is intolerable by hour 10. Build your plan with options, not rigid prescriptions.

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

Always check the official website for the most complete and current information.

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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 Ultra 100 Mile.
What is the typical race-day weather?
Based on 5 years of historical data, race-day temperatures at Leadville, Colorado typically range from 60°F to 73°F (median 68°F). Humidity ranges from 50% to 81%.
How much water should I drink?
Fluid needs vary based on your sweat rate, body weight, and race-day temperature. A typical range for moderate days is about 500-800 ml/hr, but hotter conditions at Leadville, Colorado 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 Ultra 100 Mile 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: curatedView sourceVerified: Nov 4, 2026Confidence: 80%