Early autumn · Weather & things to do
Snoqualmie Pass in September
Snoqualmie Pass cools off: highs slip to 62°F (17°C), from 69°F in August, with lows of 45°F (7°C) and about 3.0 in (76 mm) of rain.
At 86/100 for comfort (3rd of 12), it's one of the best months to visit.
- Avg high
- 62°F (17°C)
- Avg low
- 45°F (7°C)
- Rain
- 3.0 in (76 mm)
- Humidity
- 80%
- Cloud cover
- 47%
- Daylight
- ~12 h 19 min
- Comfort score
- 86/100 · Great
What September feels like
Expect mild afternoons around 62°F (17°C), good for long walks.
Lows average 45°F (7°C).
Some rain is likely, about 3.0 in (76 mm) in the month, so pack for a shower or two.
Plan around September
September is one of Snoqualmie Pass's best months on the climate data.
- Last dry month before the rain picks up: October brings 7.2 in (183 mm).
- Last of the best-scoring months: by October, the score drops to 49/100.
- Comfort slips from 97/100 in August to 86/100.
- Our Seattle, Snoqualmie Pass & Leavenworth route is planned for Late Nov – Dec, a window set by the holiday season rather than the weather — September falls outside it.
What to pack for September
- A warm layer for eveningsnights drop to 45°F
- Packable rain jacket or umbrellaabout 3.0 in of rain
- Comfortable walking shoesmost picks involve some walking
What to do in Snoqualmie Pass in September
With conditions on your side, the picks below favor time outside.
Northwest Railway Museum
Railway museum based in the 1890 Snoqualmie Depot, running its Santa Train to the falls on December weekends.
Snoqualmie Falls
A 268-foot waterfall on the Snoqualmie River, running at full force in the wet winter months.
Why now September scores 86/100 for comfort, good conditions for being outside.
Gold Creek Pond
Flat snowshoe loop around a mountain pond on the east side of the pass, reached from the Gold Creek Sno-Park.
Why now Highs near 62°F and 3.0 in of monthly rain make this an easy outdoor pick.
The Summit at Snoqualmie
Four ski areas at the top of I-90, the closest skiing to Seattle, with one of the largest night-skiing operations in the country.
Why now One to do outside while the weather is on your side.
Nearby in September
- Leavenworth in September~37 mi · highs 74°F, 1.3 in rain · 7°C (12°F) warmer by day, drier
- Seattle in September~45 mi · highs 69°F, 2.3 in rain · 4°C (7°F) warmer by day, drier
- Bainbridge Island in September~54 mi · highs 69°F, 2.3 in rain · 4°C (7°F) warmer by day, drier
- Olympic NP in September~105 mi · highs 53°F, 3.4 in rain · 5°C (9°F) cooler by day, about as wet
NASA POWER 2001–2025 monthly averages on a ~50 km grid, temperatures adjusted from the grid cell's ~1,198 m to Snoqualmie Pass's ~923 m elevation (standard lapse rate). Comfort scores weigh temperature, rain, humidity and cloud: see how we score each month. Check a forecast before you go.
Snoqualmie Pass in September: quick answers
Is September a good time to visit Snoqualmie Pass?
Yes. On the climate data it's one of the best months, scoring 86/100. Expect highs of 62°F (17°C) and 3.0 in (76 mm) of rain.
How cold is Snoqualmie Pass in September?
Average highs are 62°F (17°C) and average lows 45°F (7°C), making it the 3rd-warmest month by daytime highs.
Does it rain a lot in Snoqualmie Pass in September?
Some: about 3.0 in (76 mm) of rain falls across September on average, the 3rd-driest month of the year. The annual total is about 69.4 in (1764 mm).
What should I pack for Snoqualmie Pass in September?
Bring a warm layer for evenings (nights drop to 45°F), packable rain jacket or umbrella (about 3.0 in of rain) and comfortable walking shoes (most picks involve some walking).
More on Snoqualmie Pass
Planning Snoqualmie Pass in September?
Bring the crew into one shared trip: vote on dates, build the day-by-day plan, split costs and share one packing list.