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Summit

Thomas Mountain

Washington

About

Thomas Mountain is a summit of 5,267 feet in the Cle Elum Ranger District of the Okanogan-Wenatchee National Forest in Washington, about 1.7 miles from the town of Roslyn. Summer is the most comfortable time to go. Typical averages from the nearby Stampede Pass weather station show July and August highs around 68 to 69°F with only seven or eight wet days a month, while winter brings highs near freezing and rain on most days. The Kachess Beacon Trail #1315.3 starts less than a mile away, and the Domerie Divide Trail #1308.2 is about a mile off. For an overnight base, Wish Poosh Campground is about 3.4 miles away and East Kachess Group Site about 3.5 miles.

Summit Facts

Summit elevation

5,267 ft

Elevation from USGS 3D Elevation Program terrain data (about 10 m resolution).

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Location

Thomas Mountain

Washington

Name and location: U.S. Geological Survey, Geographic Names Information System (GNIS). Elevation: USGS 3D Elevation Program. View the GNIS record.

Facts about this place

When to go

Best time to go: Jun–Sep. The mildest months here, with typical highs of 60–69°F and lows of 43–51°F.

Typical monthly averages (not a forecast) from the Stampede Pass, WA weather station, 8.6 mi away. High / low in °F.

  1. Jan32° high25° low
  2. Feb35° high26° low
  3. Mar40° high29° low
  4. Apr46° high33° low
  5. May53° high38° low
  6. Jun60° high43° low
  7. Jul68° high50° low
  8. Aug69° high51° low
  9. Sep63° high47° low
  10. Oct49° high38° low
  11. Nov38° high30° low
  12. Dec32° high24° low

The station sits about 1,300 ft lower than this spot, so expect it to run cooler up here.

Source: NOAA NCEI U.S. Climate Normals 1991–2020

Where it is

Nearest town
Roslyn, Washington · 1.7 mi

Source: USFS EDW boundaries; USGS GNIS populated places

Conditions

Active alerts for Cle Elum Ranger District as of Oct 9, 2026:

Source: USFS forest alerts

Nearby

Source: Roamze catalog (indexable pages within 10 miles, PostGIS distance)

    Thomas Mountain — Summit in Washington | Roamze