Olympic National Park weather in September

September in Olympic National Park: cool, rainy, with clean air — a great time to visit.

Updated September 2026 · climate normals from ERA5 reanalysis

Olympic National Park🇺🇸 United States · Pacific Northwest · National park78
  1. 39Jan
  2. 47Feb
  3. 54Mar
  4. 66Apr
  5. 80May
  6. 85Jun
  7. 94Jul
  8. 96Aug
  9. 78Sep
  10. 58Oct
  11. 44Nov
  12. 35Dec

#5 of 12 months in Olympic National Park · #773 of 1413 destinations to visit in September · comfort 78/100 (tier B)

Days
14°C
Nights
6°C
Wet days
11
Sun
9.6 h
Humidity
75%
Daylight
13 h
Olympic National Park, United States
Photo: Ambient Vista · Pexels

Traveller notes on Olympic National Park in September

Olympic-forum threads on September weather are consistent this is genuinely one of the park's strongest months, noticeably drier than the notoriously wet stretch running much of the rest of the year, especially once after-Labor-Day crowds thin out. Posters call days here often sunnier than August, clear enough after dark for genuinely good stargazing given how little light pollution reaches this corner of the peninsula. Regulars describe elk as more visible this time of year, sightings along Hoh Rain Forest trails a real highlight. Posters call Lake Crescent and Lake Angeles both at their warmest for swimming by September. Regulars are direct this reputation comes with a real caveat, a run of grey, damp days entirely possible even during an otherwise favorable September. Posters recommend a hat and sun protection regardless of the changeable reputation. The record: 13.6C days feeling like 12C, 5.6C nights, an extraordinarily high 148mm across nearly 11 days and 75 percent humidity.
OlympicSeptemberRegular · September · 1 month ago · Read more on Tripadvisor ↗

Other months in Olympic National Park

Olympic-forum threads on a January visit describe Hurricane Ridge and the Sol Duc resort as genuinely closed, posters naming this a real limitation for anyone hoping to visit either spot. Regulars call the park's variety genuinely on display even in winter, several posters naming snow in the mountains, rain in the lowlands and wind along the coast within the same trip. Posters call January genuinely a better choice than November or December, several regulars naming lengthening days and more sun breaks past the eighteenth as reasons late January edges out earlier winter. Regulars call the rain shadow area a real bet for better odds of sun, several threads naming this a genuine strategy for chasing clearer weather. Posters recommend real waterproof layers regardless of which part of the park you visit, several regulars calling this standard given how much conditions vary. The record: 2.9C days, -2.6C nights, an extraordinarily high 527mm across nearly 20 days and 89 percent humidity.
OlympicJanuaryRegular · January · 1 month ago · Read more on Tripadvisor ↗
Olympic National Park-forum threads on a March visit call this genuinely one of the roughest windows of the year, posters describing the month as more an extension of winter than a real spring visit most years. Regulars call the Hoh and Quinault rainforests along with La Push and Kalaloch beaches the strongest March picks, these lower-elevation areas free of snow and road closures barring a severe storm. Posters call gaining elevation a real problem this month, snow appearing fast once a route climbs beyond the river valleys. Regulars recommend staying close to planned destinations rather than basing far away, March daylight here still limited enough that long drives eat into usable time. Posters call multi-day windstorms a genuine March hazard, conditions capable of disrupting plans for several days running. The record: 3.6C days feeling like 1C, -3.6C nights, an extraordinarily high 311.4mm across nearly 19 days and 82 percent humidity.
OlympicMarchRegular · March · 1 month ago · Read more on Tripadvisor ↗
Olympic-forum threads on a November visit describe this as genuinely one of the wettest stretches of the year, posters calling frequent rain and short days the standard rather than the exception. Regulars call wind, not snow, the real concern here, dangerous storms capable of closing the Hoh Rainforest ahead of a forecast system. Posters describe fog and overcast skies as common companions to the rain, though real breaks do occur and a light shower with a good raincoat can still be enjoyable. Regulars call conditions impossible to predict this far out, some November days turning out great and others a real washout. Posters recommend real waterproof gear and boots regardless of forecast, temperatures generally in the low fifties Fahrenheit. Regulars call the rainforest genuinely atmospheric this time of year, mist and dripping canopy part of the appeal. The record: 4.5C days feeling like 1C, -1.2C nights, an extraordinarily high 550.4mm across over 21 days and 88 percent humidity.
OlympicNPNovemberRegular · November · 1 month ago · Read more on Tripadvisor ↗
Olympic-forum threads on October describe a real split within the month - the first two to three weeks generally deliver plenty of sun and clear nights with genuine autumn color in the heaths and shrubs, while the heavier systems typically arrive by mid-month, especially on the park's west side covering the Hoh Rainforest and areas near Lake Quinault. Posters describe the wetter stretch as more steady drizzle than dramatic downpours, and note the rainforest canopy is thick enough that a light shower often goes unnoticed underneath it. A heavier, windier spell is called genuinely uncomfortable for hiking even in good gear, though posters call the rainforest atmospheric and worth it even under a gentle shower. Regulars recommend early-to-mid October for the best odds of favorable conditions. The record: 8.9C days feeling like 6C, 2.1C nights, an extraordinarily high 391mm across nearly 17 days and 83 percent humidity.
HohRainforestOctoberRegular · October · 1 month ago · Read more on Tripadvisor ↗

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Olympic National Park climate normals — September

Daytime high14°C / 56°F🙂 cool
Nighttime low6°C / 42°F
Feels like (high)12°C / 54°F
Rainfall148 mm / 5.8 in🌧 rainy
Rainy days11 days
Humidity75%💦 very humid
Dew point5°C / 41°F
Sunshine9.6 h/day
Daylight12.5 h
Wind9 km/h / 5 mph
Air quality (US AQI)31🍃 good

Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.

Crowds in Olympic National Park in September

How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.

Peak crowdsThe dry window, Labor Day weekend, Summer break in United States(estimated)

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Peak crowdsBusyShoulder seasonQuiet

Best months for Olympic National Park's weather

Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).

Fair weatherOlympic National Park's weather peaks June–August.

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Best weatherFair weatherToughest weather

What's on in Olympic National Park in September

Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.

  • Opening

    High country opens

    1 Jul – 10 Oct · usuallyTrail season

    Obstruction Point Road, Deer Park and the high traverses only clear in July, weeks after the rainforest has greened up. Before then the ridge is a snowshoe, not a walk. Source ↗

  • Season

    The dry window

    5 Jul – 15 SepDry seasonCrowded

    The wettest corner of the lower 48 takes about ten weeks off in high summer. It is the only stretch when the coast, the rainforest and the ridge all work on one trip, and everyone knows it.

  • Holiday

    Labor Day weekend

    5–7 SepNational holidayCrowdedBook early

    Labor Day, the first Monday of September, is the last big getaway of summer: the long weekend books out campsites and lodging and fills parking early, and families thin out quickly once it has passed. Source ↗

  • Nature

    Coho Salmon Run

    1 Sep – 31 Oct · usuallyWildlife season

    Coho salmon push up the Sol Duc River each fall and leap the falls at Salmon Cascades; a short, wheelchair-accessible viewing platform off Highway 101 makes it one of the park's easiest wildlife sightings. Source ↗

  • Nature

    Roosevelt elk rut

    5 Sep – 20 Oct · usuallyWildlife season

    Bulls bugle through the Hoh and Queets valleys from early September, and the sound carries a long way under that canopy. Keep well back; they are the largest elk in North America and unbothered by people.

What's on around the world in September →

Nearby, and something's on

Within 300 km of Olympic National Park — a day trip or a short hop — with something on this month. Never part of the comfort score.

Where is Olympic National Park?

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Olympic National Park in September — FAQ

Is September a good time to visit Olympic National Park?
September in Olympic National Park: cool, rainy, with clean air — a great time to visit. It ranks #5 of 12 months for Olympic National Park on SeasonMap's comfort score (78/100).
What is the weather like in Olympic National Park in September?
In September, Olympic National Park averages a daily high of 13.6°C and a low of 5.6°C, with about 147.6 mm of rain over roughly 10.5 rainy days.
What is the air quality in Olympic National Park in September?
Olympic National Park has a mean US Air Quality Index of about 31 in September.

Within 300 km: Victoria, BC's Whale watching season around 1 May – 15 Oct, and Seattle's Salmon at the Ballard Locks around 15 Jun – 20 Sep.