Summit forecast for 4,902 ft · Twin · Updated 3x daily
As of August 16, 2026 at 8:20 PM ET
South Twin Mountain (4,902 ft) is currently 51°F (feels like 45°F) with mainly clear and SSE winds at 13 mph, gusting to 23 mph. Today's freezing level is 13,189–15,026 ft. Expect the summit to run about 11°F colder than the trailhead. Trail conditions are rated Moderate.
Valley forecasts don't apply up high — temperatures drop about 3.2°F per 1,000 ft on South Twin Mountain.
| Elevation | Temp Range | Max Wind | Wind Chill (Low) |
|---|---|---|---|
| Summit 4,902 ft | 48° – 55°F | 26 mph | 40°F |
| Treeline 4,000 ft | 49° – 57°F | 25 mph | 41°F |
| Trailhead 2,000 ft | 52° – 66°F | 12 mph | 52°F |
Freezing level today: 13,189–15,026 ft
~3.2°F drop per 1,000ft
Tap a day header to expand to 3hr or hourly detail
Sunday Aug 16 | Today Aug 17 | Tomorrow Aug 18 | |||||||
|---|---|---|---|---|---|---|---|---|---|
| AM | PM | night | AM | PM | night | AM | PM | night | |
| Temperature & Wind | |||||||||
| Weather | fog | cloudy | drizzle | rain | fog | fog | fog | drizzle | cloudy |
| Temp °F hi / lo | 51° 50° | 54° 51° | 56° 54° | 56° 55° | 60° 57° | 59° 56° | 56° 53° | 57° 52° | 57° 55° |
| Chill °F | 45° | — | — | — | — | — | — | — | — |
| Wind mph | 13 | 22 | 33 | 28 | 18 | 6 | 9 | 8 | 8 |
| Gust mph est. | 21 | 35 | 53 | 45 | 29 | 10 | 14 | 13 | — |
| Storm risk | — | — | — | — | mod | mod | — | — | — |
| Precipitation | |||||||||
| Precip in (rain/snow) | - | - | 0.0 | 0.3 | - | - | - | - | - |
| Freezing ft | 14,298 ft | 14,550 ft | 14,485 ft | ||||||
| Conditions | |||||||||
| Cloud cover | 18% | 100% | 100% | 100% | 100% | 100% | 100% | 100% | 100% |
| Vis mi | 0.4 | 8 | <0.1 | <0.1 | <0.1 | <0.1 | <0.1 | 4 | clear |
| UV | 5 | 7 | — | 0 | 3 | — | 3 | 7 | — |
Tap a day header to expand AM/PM/Night detail
| Elevation | Sunday Aug 16 | Today Aug 17 | Tomorrow Aug 18 |
|---|---|---|---|
| lo/hi °F · wind mph & dir · chill °F | |||
| Summit 4,902 ft | 50/51° 13 | 55/56° 28 | 53/56° 9 |
| 4,100 ft | 50/52° 13 | 57/58° 26 | 54/58° 13 |
| 3,300 ft | 51/54° 11 | 59/60° 21 | 56/59° 13 |
| 2,500 ft | 51/58° 8 | 61/62° 14 | 58/61° 11 |
| Trailhead 2,000 ft | 52/60° 6 | 63/64° 12 | 60/63° 9 |
4 more days of forecast — plan around the weather window, not just tomorrow.
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.
As of August 16, 2026 at 8:20 PM ET: South Twin Mountain (4,902 ft) is currently 51°F (feels like 45°F) with mainly clear and SSE winds at 13 mph, gusting to 23 mph. Today's freezing level is 13,189–15,026 ft. Expect the summit to run about 11°F colder than the trailhead. Trail conditions are rated Moderate.
Temperatures drop roughly 3.2°F per 1,000 ft of elevation on South Twin Mountain. Today the trailhead (2,000 ft) tops out around 66°F while the summit (4,902 ft) reaches about 55°F, with a wind chill as low as 40°F.
Winds at the summit of South Twin Mountain are forecast to reach 26 mph today, with 25 mph at treeline. Above treeline there is no shelter from wind — plan layers around wind chill, not air temperature.
Today's freezing level (13,189–15,026 ft) is above the 4,902 ft summit of South Twin Mountain, so the full route should stay above freezing.