The Mount Flume via Osseo Trail is a 10.5-mile out-and-back with 3,122 ft of elevation gain.
10.5 mi • 3,122 ft gain • 5-9 hours • Lincoln Woods Trailhead
Feels like 33°F
Recent Precipitation
Rain: 0.11" (24h) · 0.11" (48h)
Best Hiking Window
Conditions synthesized from: NWS Higher Summits Forecast, NOAA Open-Meteo, Mount Washington Observatory, NETC Trip Reports, NOHRSC Snow Depth, Mt. Washington Avalanche Center, USGS Stream Levels, OpenWeather Air Quality.
AI-generated from public data. Always verify conditions before heading out — backcountry weather can change quickly.
Summit-level conditions by time of day at 4,328' elevation
Tap a day header to expand to 3hr or hourly detail
Today Oct 5 | Tomorrow Oct 6 | Wednesday Oct 7 | |||||||
|---|---|---|---|---|---|---|---|---|---|
| AM | PM | night | AM | PM | night | AM | PM | night | |
| Temperature & Wind | |||||||||
| Weather | rain | fog | fog | fog | fog | cloudy | cloudy | cloudy | cloudy |
| Temp °F hi / lo | 45° 41° | 42° 32° | 29° 23° | 24° 23° | 29° 24° | 38° 30° | 44° 40° | 48° 42° | 51° 47° |
| Chill °F | 30° | 16° | 2° | 2° | 6° | 15° | 32° | 31° | 36° |
| Wind mph | 30 | 40 | 45 | 45 | 35 | 30 | 15 | 29 | 44 |
| Gust mph est. | 48 | 56 | 63 | 63 | 56 | 48 | 24 | 46 | 62 |
| Storm risk | — | — | — | — | — | — | — | — | — |
| Precipitation | |||||||||
| Precip in (rain/snow) | 0.2 | - | - | - | - | - | - | - | - |
| Chance of precip | 33% | 26% | 4% | 4% | 1% | - | 1% | 1% | 5% |
| Freezing ft | 4,935 ft | 3,522 ft | 10,091 ft | ||||||
| Conditions | |||||||||
| Cloud cover | 100% | 100% | 100% | 100% | 100% | 100% | 100% | 100% | 100% |
| Vis mi | <0.1 | <0.1 | <0.1 | <0.1 | <0.1 | clear | clear | clear | clear |
| UV | 2 | 5 | — | 1 | 3 | — | 3 | 5 | — |
Tap a day header to expand AM/PM/Night detail
| Elevation | Today Oct 5 | Tomorrow Oct 6 | Wednesday Oct 7 |
|---|---|---|---|
| lo/hi °F · wind mph & dir · chill °F | |||
| Summit 4,328 ft | 41/45° 30 | 23/24° 45 | 40/44° 15 |
| 4,100 ft | 42/46° 29 | 24/25° 44 | 40/44° 13 |
| 3,300 ft | 45/47° 23 | 27/28° 36 | 40/43° 9 |
| 2,500 ft | 47/49° 16 | 30/31° 27 | 40/45° 9 |
| Trailhead 2,000 ft | 49/51° 14 | 32/33° 22 | 38/48° 7 |
4 more days of forecast: plan around the weather window, not just tomorrow.
Full hourly summit forecasts: Mount Flume weather
Follows the Lincoln Woods Trail and the Osseo Trail from the Kancamagus Highway, climbing a long ridge with a series of wooden staircases to the Franconia Ridge Trail and the summit's sharp, exposed ledges. The Flume Slide Trail is a steep, slabby alternative best avoided when wet.
Distance
10.5 mi
Elevation Gain
3,122 ft
Duration
5-9 hours
Trailhead
Lincoln Woods Trailhead
The Mount Flume via Osseo Trail is 10.5 miles round trip, starting at Lincoln Woods Trailhead. At AMC book time (half the distance in hours plus 30 minutes per 1,000 ft of climbing), that works out to roughly 5-9 hours. Most parties take longer than book time on rough or above-treeline terrain, in winter, or with a heavy pack.
The Mount Flume via Osseo Trail climbs about 3,122 ft over 10.5 miles, an average of roughly 296 ft of gain per mile. That figure is cumulative ascent across the whole out-and-back, not the difference between the trailhead and the high point.
HikerNerd rates the Mount Flume via Osseo Trail Hard on a six-tier scale from Easy to Most demanding. The rating comes from the route itself: its 10.5 miles, 3,122 ft of gain, and the steepest quarter mile of trail, with routes known for scrambles or ledges rated a step harder. It is the same scale our NH 4,000-footer difficulty ranking uses. Above-treeline exposure, water crossings, and winter conditions can still make a well-rated route the hardest day of your year, so check current conditions before committing.
The Mount Flume via Osseo Trail summits 1 named peak: Mount Flume.
The Mount Flume via Osseo Trail starts at Lincoln Woods Trailhead. Check the trail alerts on this page before you drive: trailhead access and parking in the White Mountains change with closures and construction.
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