Races›Ultra 50K

Greenland Trail Races

Race-specific weather data and nutrition strategy for Greenland Trail Races in Larkspur, CO, US.

RunningUltra 50K (31.1 mi)Registration Open
LocationLarkspur, CO, US
Date
May 1, 2027
Register on RunSignUpBuild Your Fueling PlanOfficial website
Race Location39.18°, -104.85°
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Race-Day Conditions

Low Heat Risk
Temperature
60°F

45–68°F range

Humidity
60%

35–85% range

5-year average via Open-Meteo. 80% of race days fall within the range shown. Updated Jun 8, 2026.

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Favorable temperature range

Typical race-day temperature of 60°F is in the optimal range for performance. Standard fueling and hydration targets apply.

Sample Ultra 50K Nutrition Plan

Based on a 155 lb runner finishing in ~6 hours. Your plan will differ based on body weight, experience, and conditions.

HourCarbsFluidSodiumExample
Hour 150g16oz400mg1 gel + sports drink
Hour 265g18oz500mg2 gels + water
Hour 365g18oz500mgChews + drink mix
Hour 460g18oz500mgGel + banana
Hour 555g16oz500mgPB sandwich + water
Hour 650g14oz400mgGel + sports drink
Total345g100oz2800mg

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

What to Expect at Greenland Trail Races

Greenland Trail Races is a Ultra 50K (31.1 mi) ultra 50k held in Larkspur, CO, US. Based on 5 years of historical weather data, athletes can expect median race-day temperatures around 60°F.

Temperatures at Greenland Trail Races typically range from 45°F to 68°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.

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.

See something wrong? Let us know and we'll fix it.

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 50K.
What is the typical race-day weather?
Based on 5 years of historical data, race-day temperatures at Larkspur, CO typically range from 45°F to 68°F (median 60°F). Humidity ranges from 35% 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 Larkspur, CO 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 50K 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_apiView sourceVerified: Jun 8, 2026Confidence: 95%