Races
Lake Cuyamaca loop. Four county mountain zones. Looks tame on paper. Rocks, roots, heat, and 15,600 feet of climbing say otherwise.
Field, 2026 · 25-year samplescraped
Geometryderived
Course records
The cruxNoble Canyon and exposed PCT ridges in afternoon heat (near mile 65)
Course DNA
San Diego 100 runs 100 mi through Lake Cuyamaca, California. +10,207 ft gain and -10,206 ft loss. Surfaces skew 90% singletrack / 10% dirt road. Noble Canyon and exposed PCT ridges in afternoon heat. High point near 6,411 ft. Low near 3,672 ft. April temps run 40°F to 95°F. The course rewards patience early and punishes rushed descents after mile 50.
Train for 10,207 feet of climbing across 100 mi. Back-to-back long runs on similar surfaces. Practice power-hiking grades above 15 percent. 32 hours total means limited margin: rehearse fueling every 45 to 60 minutes and downhill eccentric work weekly. Technicality 5/10. Build a block that simulates the crux near mile 65.
April in Lake Cuyamaca, California: plan for 40°F to 95°F. Mandatory shell if rain is in forecast. Headlamp with spare batteries if 32 hours pushes past dark. Poles help on sustained climbs above mile 25. Vest capacity for 2 liters minimum. Shoes matched to 90% singletrack: lugs for mud, rock plate if the course turns technical after mile 50.
Hold effort through mile 25. The field often splits on the first big climb after mile 50. Noble Canyon and exposed PCT ridges in afternoon heat near mile 65 is where time is won or lost. Walk the steep pinches. Run the flats and gentle downhills. Crew at major aids: socks, calories, ice if hot. Transitions under 5 minutes when possible. Final third is 33 miles of fatigue management. Finish with reserve for the last descent.
Results
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