Washington mountains

Mesahchie Peak mountain forecast

8,796 ft (2,681 m) · prominence 2,234 ft (681 m) · Washington

At the summit’s height the GFS model has 20°F and wind from the WNW at 14 mph, a wind chill of 6°F, Sat, Sep 26, 5:00 AM PDT. The freezing level is at 4,140 ft, 4,656 ft below the summit. The National Weather Service forecast for saturday: mostly sunny, high 37°F at its grid elevation of 6,165 ft.

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The summit on the map

Mesahchie Peak and the summits and ski areas around it. Each has its own page.

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Now

Summit
8,796 ft (2,681 m)
Forecast grid ground
6,165 ft (1,879 m)
Summit temperature
20°F
Summit wind
WNW 14 mph
Freezing level
4,140 ft
High at the summit, by lapse rate
28°F

The last tile carries the Weather Service’s high from its grid’s 6,165 ft up 2,631 ft to the summit at the standard atmosphere’s 6.5 °C per kilometer (about 3.6 °F per 1,000 ft). Real lapse rates vary: an inversion can make the summit warmer than the valley.

At the summit’s height

Temperature, wind and wind chill up there, and the freezing level, every six hours for three days.

TimeTempWindWind chillFreezing level
Sat, Sep 26, 5:00 AM PDT20°FWNW 14 mph6°F4,140 ft4,656 ft below the summit
Sat, Sep 26, 11:00 AM PDT25°FWNW 5 mph18°F5,774 ft3,022 ft below the summit
Sat, Sep 26, 5:00 PM PDT29°FWSW 4 mph24°F7,349 ft1,447 ft below the summit
Sat, Sep 26, 11:00 PM PDT29°FSSW 3 mph26°F7,021 ft1,775 ft below the summit
Sun, Sep 27, 5:00 AM PDT30°FSW 3 mph27°F6,437 ft2,359 ft below the summit
Sun, Sep 27, 11:00 AM PDT32°FWSW 4 mph28°F7,972 ft823 ft below the summit
Sun, Sep 27, 5:00 PM PDT33°FWSW 5 mph28°F8,530 ft266 ft below the summit
Sun, Sep 27, 11:00 PM PDT31°FWSW 7 mph25°F7,638 ft1,158 ft below the summit
Mon, Sep 28, 5:00 AM PDT30°FW 10 mph22°F8,885 ft89 ft above the summit
Mon, Sep 28, 11:00 AM PDT34°FW 10 mph26°F8,786 ft10 ft below the summit
Mon, Sep 28, 5:00 PM PDT34°FWSW 12 mph25°F8,412 ft384 ft below the summit
Mon, Sep 28, 11:00 PM PDT32°FWSW 19 mph21°F8,668 ft128 ft below the summit

NOAA’s GFS model, run Fri, Sep 25, 11:00 PM PDT, interpolated to 8,796 ft between its pressure levels: the free air over the summit, which on a ridge is close to what a climber feels and in a sheltered spot is more than it. Wind chill is the National Weather Service’s formula, given where the temperature is 50°F or less and the wind above 3 mph.

The National Weather Service forecast at the summit

PeriodTempWindForecast
OvernightLow 27°FW 15 mphA chance of snow. Mostly cloudy. Low around 27, with temperatures rising to around 30 overnight. Wind chill values as low as 19. West wind around 15 mph. Chance of precipitation is 40%. New snow accumulation of around one inch possible.
SaturdayHigh 37°FWNW 5-15 mphMostly sunny, with a high near 37. Wind chill values as low as 18. West northwest wind 5 to 15 mph. Little or no snow accumulation expected.
Saturday NightLow 28°FESE 2-10 mphPartly cloudy, with a low around 28. Wind chill values as low as 20. East southeast wind 2 to 10 mph.
SundayHigh 44°FSSW 2-9 mphSunny, with a high near 44. Wind chill values as low as 19. South southwest wind 2 to 9 mph.
Sunday NightLow 30°FW 2-8 mphMostly clear, with a low around 30. West wind 2 to 8 mph.
MondayHigh 44°FW 5-12 mphMostly sunny, with a high near 44.
Monday NightLow 33°FSW 12-16 mphA chance of rain between 11pm and 2am, then rain and snow. Mostly cloudy, with a low around 33. Little or no snow accumulation expected.
TuesdayHigh 37°FSW 8-14 mphRain and snow before 5pm, then rain and snow likely. Cloudy, with a high near 37. Little or no snow accumulation expected.
Tuesday NightLow 32°FWSW 8-15 mphRain and snow likely. Mostly cloudy, with a low around 32.
WednesdayHigh 40°FWSW 6-10 mphA slight chance of rain and snow. Partly sunny, with a high near 40.

The Weather Service’s forecast asked at the summit’s coordinates (48.5786, -120.8800), by its office in Seattle/Tacoma, WA. Its grid cell is 2.5 km across and sits at 6,165 ft (1,879 m), 2,631 ft below the summit, so its temperatures and winds are for that height.

Cloud base and the summit

TimeSkyTemp and dew pointCloud base
Sat, Sep 26, 5:00 AM PDTSlight Chance Light Snow30°F / 25°F7,309 ftSummit likely in cloud
Sat, Sep 26, 11:00 AM PDTMostly Sunny29°F / 25°F7,063 ftBase below the summit if cloud forms
Sat, Sep 26, 5:00 PM PDTSunny37°F / 26°F8,680 ftBase below the summit if cloud forms
Sat, Sep 26, 11:00 PM PDTPartly Cloudy30°F / 22°F7,992 ftBase below the summit if cloud forms
Sun, Sep 27, 5:00 AM PDTMostly Cloudy29°F / 19°F8,430 ftSummit likely in cloud
Sun, Sep 27, 11:00 AM PDTSunny39°F / 20°F10,498 ftBase above the summit
Sun, Sep 27, 5:00 PM PDTSunny44°F / 24°F10,735 ftBase above the summit
Sun, Sep 27, 11:00 PM PDTMostly Clear32°F / 22°F8,443 ftBase below the summit if cloud forms
Mon, Sep 28, 5:00 AM PDTPartly Cloudy30°F / 19°F8,676 ftBase below the summit if cloud forms
Mon, Sep 28, 11:00 AM PDTMostly Sunny39°F / 20°F10,498 ftBase above the summit
Mon, Sep 28, 5:00 PM PDTPartly Sunny42°F / 29°F9,145 ftBase above the summit
Mon, Sep 28, 11:00 PM PDTChance Light Rain36°F / 28°F7,979 ftSummit likely in cloud

An estimate: the height a rising parcel of the grid’s air would reach saturation, about 125 m for every degree Celsius between temperature and dew point (Espy’s rule), added to the grid’s ground. It fits cumulus and fog made on the spot, not a deck of stratus carried in from elsewhere.

Snow

September 25: 0.9 in · September 26: 0.9 in · September 29: 0.1 in. 1.9 inches in all. Snow level as low as 4,757 ft.

National Weather Service snowfall at the grid cell over the summit.

Sunrise and sunset

DayFirst lightSunriseSunsetLast lightDaylight
September 266:25 AM6:56 AM6:55 PM7:26 PM-13h -1m
September 276:26 AM6:58 AM6:53 PM7:24 PM-13h -5m
September 286:28 AM6:59 AM6:50 PM7:22 PM-13h -9m
September 296:29 AM7:00 AM6:48 PM7:20 PM-13h -12m
September 306:31 AM7:02 AM6:46 PM7:17 PM-13h -16m
October 16:32 AM7:03 AM6:44 PM7:15 PM-13h -19m
October 26:33 AM7:05 AM6:42 PM7:13 PM-13h -23m

For a sea-level horizon at the summit’s position, local time. From a summit the horizon sits lower, so the sun is seen a few minutes before sunrise and after sunset; a ridge to the east or west does the opposite.

Avalanche forecast

Mesahchie Peak is in the East Slopes North zone of the Northwest Avalanche Center. Status: off season: a summary, no rating.

Elevation
8,796 ft (2,681 m)
Prominence
2,234 ft (681 m)
Coordinates
48.5786, -120.8800
Nearest town
Twisp

What this means

Why a summit forecast differs
The air cools with height, by about 3.6°F per 1,000 feet on average, and the wind above a ridge blows at the speed of the free atmosphere rather than slowed by the valley floor. A town’s forecast says little about the top of the mountain above it.
Freezing level
The height where the air is at 32°F (0°C). Above it precipitation falls as snow and wet rock freezes; the snow line usually sits a few hundred to a thousand feet below it.
Wind chill
How cold the air feels on exposed skin, from the temperature and the wind, by the National Weather Service’s 2001 formula.
Cloud base
Where cloud begins. When it is below the summit, the top is in cloud: no view, and in cold air, rime ice and poor visibility.
Prominence
How far a summit rises above the lowest contour line that encircles it and no higher summit: the measure of a mountain’s own height, not its neighbors’.

Nearby

Summits

Forecasts from the National Weather Service. Summit-height temperature, wind and freezing level from NOAA’s Global Forecast System on NOAA Open Data. Summits from Wikidata (CC0): prominence >= 600 m, or elevation >= 4267 m, or >= 12 Wikipedia editions; English Wikipedia article required; read 2026-09-25. Mountain weather changes fast; check the forecast again before you go.