All Trails

Mount Si

The most hiked trail in Washington state. 8 miles round trip with 3,150 ft gain through old-growth forest. Optional Class 3 haystack scramble at top.

ModeratePacific NW3,900 ftForested

Mount Si

⛅ Partly cloudy

Good to Go
36°
Feels 36°FSummit · 3,900 ft
6:11 AM8:00 PM
CLEAR

Wind

2mph

Precip

1%

Humid

46%

Elev Δ

+3200ft

12-Hour Temp Trend

53°71°

Hourly Forecast

7 AM

⛅

53°

7mph

8 AM

⛅

55°

6mph

9 AM

⛅

61°

4mph

10 AM

⛅

65°

5mph

11 AM

⛅

67°

8mph

12 PM

⛅

68°

10mph

1 PM

⛅

69°

11mph

2 PM

⛅

69°

12mph

3 PM

⛅

70°

10mph

4 PM

⛅

71°

7mph

5 PM

⛅

71°

2mph

6 PM

⛅

71°

2mph

Summit Conditions

54°F→−18°→36°F

Dry lapse rate: 5.4°F/1,000ft · 3,211 ft gain

◎L1
Merino wool 200g base layer

Medium-weight merino regulates temp and resists odor on long days

◉L2
Grid fleece jacket

Stretchy grid fleece balances warmth and breathability on climbs

◈L3
Wind shell jacketPACK

Blocks summit wind without trapping sweat on the approach

Summit Pack List

↟Wind shell↟Light puffy (optional)↟Beanie↟Light gloves

Start Cold Tip

Start in your base + fleece. You'll warm up on the switchbacks. Pack your wind shell for the exposed ridge — wind hits different above treeline.

Updated 6:44:33 AM · America/Los_Angeles

Updated Apr 19, 6:44 AM UTC

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