Races›Ultra 50 Mile

American River 50

American River 50 is Apr 3, 2027 in Folsom to Auburn. Build your free hour-by-hour plan.

RunningUltra 50 MileRegistration Open
LocationFolsom to Auburn, California, US
Date
April 3, 2027
Build Your Fueling PlanOfficial website
Race Location38.69°, -121.13°
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Race-Day Conditions

Moderate Heat Risk
Temperature
67°F

55–78°F range

Humidity
69%

58–80% range

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

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Moderate heat risk

Temperatures may reach 78°F. Plan for 10-15% higher sweat rates than cool conditions. Ensure adequate sodium intake (600-900 mg/hr) and consider pre-cooling strategies.

Sample Ultra 50 Mile Nutrition Plan

Based on a 155 lb runner finishing in ~10 hours. Your plan will differ based on body weight, experience, and conditions.

HourCarbsFluidSodiumExample
Hour 150g18oz400mg1 gel + sports drink
Hour 265g20oz500mg2 gels + water
Hour 365g20oz500mgChews + drink mix
Hour 460g20oz500mgGel + banana
Hour 555g18oz500mgRice ball + water
Hours 6–10250g88oz2500mgMix of gels, food, broth
Total545g184oz4900mg

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

What to Expect at American River 50

American River 50 is a 50-mile ultra held in Folsom to Auburn, California, US. Based on 5 years of historical weather data, athletes can expect median race-day temperatures around 67°F.

Temperatures at American River 50 typically range from 55°F to 78°F. The upper end of that range crosses into moderate heat risk. While not extreme, sweat rates will be elevated and athletes who under-fuel on sodium or fluids may feel it in the later miles. A dialed-in hydration plan makes a real difference here. Humidity is also a factor here, with levels reaching 80% 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.

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 50 Mile.
What is the typical race-day weather?
Based on 5 years of historical data, race-day temperatures at Folsom to Auburn, California typically range from 55°F to 78°F (median 67°F). Humidity ranges from 58% to 80%.
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 Folsom to Auburn, California 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 50 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%