Leadville 100 Course
Sawatch Range, CO
Elevation Profile
Current Conditions
Bottom Line
Good running weather — sunny, calm, and cold. The limiting factor this week is the short window: sunset at 4:56 PM means you're done by then or you're running in the dark. Stream crossing data pulled from California gauges and doesn't apply here — treat any crossings at Leadville-area drainages as unknown until you can scout them. No snow instability concerns.
48°/18°F · Sunny
Low (1/5)
Data temporarily unavailable
This data source did not respond. Try regenerating the briefing.
Elevated flows · 5 gauges
No active fires within 50 miles
10h 11m daylight · Sunrise 6:45 AM · Sunset 4:56 PM
Full Briefing
The weather window this week is about as clean as November in the Leadville basin gets. Highs in the mid-to-upper 40s, calm winds under 10 mph, and full sun Wednesday through Friday. No afternoon thunderstorm risk — this is a stable high-pressure pattern, not summer monsoon season. Cold overnight lows (18-19°F) mean any wet or muddy sections from previous days will refreeze hard by morning, so expect firm or icy trail surfaces on north-facing aspects and shaded drainages in the first few hours of your run. That's the main footing hazard — not deep snow, just refrozen mud and any residual snow patches on north slopes above treeline.
The real constraint is daylight. You have 10 hours and 11 minutes from sunrise to sunset, with the sun down at 4:56 PM. If you're running a significant stretch of the LT100 course — say, the Hope Pass segment or a Winfield-to-Twin Lakes push — work backward from 4:56 PM and be honest about your pace at elevation. A 20-mile loop starting at 8 AM gives you roughly 9 hours of usable light before golden hour degrades visibility. That's workable at a solid pace, but it leaves no buffer for navigation issues or slower-than-expected legs. Start early, turn around with enough time in the bank, or know exactly where your headlamp is.
Stream crossing data in this briefing is garbage — the five gauges cited are California stations and have zero relevance to Leadville drainages. Lake Fork, South Fork of the South Platte, and other crossings on the LT100 course need to be scouted or locally sourced before you depend on them. November flows at Leadville elevations are typically low, but don't assume — check with Leadville locals or recent trip reports.
Avalanche danger is Low across all elevations, no problems identified. This is a non-issue for trail running. Fire risk is zero. Dress for the temperature swing — it'll feel cold at the start and reasonable by midday, but the high of 48°F at Leadville's 10,152-foot base means wind chill on any exposed ridgeline will be notable even at the forecast 5 mph winds. Plan your layers around a cold start and a warm-ish midday, and remember you lose the warmth fast once the sun drops — build in enough time to be descending before 4 PM.
Waypoints
Leadville Start/Finish
Historic 6th Street in Leadville. Race begins at 4 AM.
10,151 ft
Twin Lakes
Major aid station at Twin Lakes. Pacer pickup point outbound.
9,199 ft
Hope Pass Summit
High point at 12,600 ft. The crux of the course, crossed twice.
12,598 ft
Winfield Turnaround
Ghost town of Winfield. Turnaround point for the out-and-back.
10,000 ft
Route Details
Distance
100.0 mi
Elevation Gain
15,748 ft
Elevation Loss
15,748 ft
Max Elevation
12,598 ft
Estimated Days
1.5
Trailhead
Leadville, 6th Street
Best Season
Race held in August. Course runnable July-September at altitude.
About This Route
The Leadville Trail 100 is America's most famous mountain ultramarathon, an out-and-back course through the Colorado Rockies at extreme altitude. The entire course stays above 9,200 feet, with the high point at Hope Pass (12,600 ft) crossed twice—once in each direction. Starting and finishing in historic Leadville (10,152 ft), the course traverses the Sawatch Range through a mix of mining roads, singletrack, and river valleys. The Twin Lakes section, the climb over Hope Pass, and the exposed ridgeline to Winfield turnaround are the signature sections. The altitude is the defining challenge. Even elite runners slow dramatically above 12,000 feet. The 30-hour cutoff is generous by some standards but the altitude makes it brutally selective. Night running through the Colorado mountains adds another dimension. The race has been held since 1983 and is one of the original American ultras.
Plan This Route
Get a personalized conditions briefing with detailed analysis for your trip dates.
Plan This Route