September in Seattle is the last full month of dry weather before the rain returns in October and doesn't let up until June. Daytime highs sit around 21°C (70°F), nights cool to 13°C (55°F), and the city sees roughly 50mm of rain spread across about 7 days. Compare that to October's 111mm or December's 201mm, and you'll understand why locals treat every clear September afternoon like borrowed time. The summer crowds that pack Pike Place Market and Capitol Hill from June through August thin out after Labor Day weekend. Hotel rates drop from the July-August peak. Restaurant patios in Fremont and Ballard stay open, and you might actually score a table without a 45-minute wait.
The one real concern is wildfire smoke. Fire seasons in Eastern Washington, Oregon, and Northern California tend to peak in August and September. Some years the skies stay blue from the 1st to the 30th. Others bring days of haze thick enough to erase Mount Rainier from the Kerry Park viewpoint entirely. There's no way to predict it more than a week or so out, and if you have respiratory issues, that uncertainty is worth factoring into your plans.
When the smoke stays away, though, September in Seattle is hard to beat. PAX West draws tens of thousands to the Washington State Convention Center over Labor Day weekend. Fresh-hop beers appear in Ballard taprooms within hours of the Yakima Valley harvest. The Coho salmon run starts, visible from the fish ladder at the Ballard Locks. And the light shifts. September afternoons have a golden, lower-angle quality that July's harsh midday sun never quite matches. Check AirNow.gov forecasts before booking, and consider trip insurance if smoke is a dealbreaker.
Why visit in September
- The tail end of dry season. September averages 50mm of rain across 7 days, a fraction of October's 111mm. Clear skies and 21°C (70°F) highs are common, especially in the first 2-3 weeks.
- Summer crowds drop sharply after Labor Day. Pike Place Market, the Space Needle, and Chihuly Garden and Glass all have shorter queues than July or August.
- Fresh-hop beer season. Yakima Valley hops are harvested and brewed within 24 hours. Breweries across Ballard and Georgetown release limited fresh-hop IPAs through September and early October.
- Peak harvest at farmers markets. Washington Honeycrisp apples, chanterelle mushrooms, wild blackberries, and Pacific Northwest pears all arrive at the Ballard Farmers Market and University District Farmers Market simultaneously.
- Mount Rainier's high-elevation trails at Paradise remain snow-free and accessible, with fewer hikers than the summer peak. The wildflower meadows still hold some late-season blooms into early September.
Worth knowing
- Wildfire smoke from Eastern Washington, Oregon, and California fires can settle over Puget Sound with little warning. In bad smoke years, the Air Quality Index can reach 150+ (unhealthy) for 3-7 consecutive days, limiting outdoor plans.
- The weather is a coin flip in the second half of the month. Late September can feel like early autumn, with gray mornings, rain systems moving in off the Pacific, and highs dropping closer to 18°C (64°F).
- Labor Day weekend (first weekend) still carries summer pricing and crowds, especially near the Convention Center due to PAX West. Downtown hotel rates during PAX can match or exceed July levels.
- Daylight shrinks noticeably. Seattle goes from about 13.5 hours of daylight on September 1 to 12 hours by September 30. Evening outdoor plans need to wrap earlier than in summer.
Best for
Think twice if
September sits at the hinge between Seattle's dry summer and its long, gray rainy season. The first half of the month often feels like August's quieter twin, with clear skies and warm afternoons. The second half brings more cloud cover and the occasional Pacific rain system. Mornings near the waterfront can start cool at 13°C (55°F), with the kind of damp chill that catches you off guard if you step out in a t-shirt. By noon the air warms to 21°C (70°F) and the chill burns off. Humidity averages 76%, which sounds high but rarely feels sticky at these moderate temperatures. The 50mm of rain across about 7 days is light and intermittent. Seattle rain in September is not the torrential downpour visitors fear. It's more of a fine mist that locals barely acknowledge.
Seasonal caution
- Wildfire smoke from Eastern Washington, Oregon, and Northern California wildfires can drift into the Puget Sound basin in September. Some years bring a week or more of AQI readings above 150 (unhealthy). Pack N95 masks, monitor AirNow.gov daily, and have indoor alternatives planned for every outdoor activity.
- Morning fog is common in September, particularly near the water and in low-lying areas like the Duwamish Valley. It typically burns off by 10-11am but can delay ferry schedules and reduce visibility for early-morning drives on I-90 or Highway 2 over the Cascades.
Year-round climate
Averages from the last 5 years.
| Month | Avg high (°C) | Avg low (°C) | Rainfall (mm) |
|---|---|---|---|
| Jan | 8 | 3 | 171 |
| Feb | 8 | 2 | 109 |
| Mar | 11 | 4 | 98 |
| Apr | 13 | 6 | 73 |
| May | 17 | 9 | 56 |
| Jun | 21 | 12 | 48 |
| Jul | 25 | 15 | 7 |
| Aug | 25 | 15 | 31 |
| Sep | 21 | 13 | 50 |
| Oct | 15 | 9 | 111 |
| Nov | 10 | 6 | 172 |
| Dec | 8 | 4 | 201 |
Headline events
PAX West
Labor Day weekend (late August to early September)
The largest gaming convention on the West Coast fills the Washington State Convention Center in downtown Seattle over Labor Day weekend. Panels, playable demos, esports tournaments, and cosplay draw tens of thousands of attendees. The surrounding blocks of downtown become a second convention floor, with pop-up events, sponsored lounges, and after-parties in Pioneer Square and Capitol Hill venues. Four-day badges typically sell out months in advance.
Best things to do in September
Hike the Skyline Trail at Mount Rainier
hikingThe 5.5-mile Skyline Trail loop at Paradise climbs through subalpine meadows to panoramic views of the Nisqually Glacier and the Tatoosh Range. September brings thinner crowds than August and the last of the wildflower season at 1,650m elevation.
Snow has melted from high trails by September, and the summer parking chaos at Paradise eases after Labor Day. Late-season asters and gentians still dot the meadows.Booking tipArrive at the Paradise lot before 9am on weekends. The National Park Service timed-entry reservation system typically ends after Labor Day, but check nps.gov/mora for the current year's dates.
Watch salmon at the Ballard Locks
natureThe fish ladder at the Hiram M. Chittenden Locks in Ballard has underwater viewing windows where you can watch Coho and Chinook salmon swimming upstream from Puget Sound to the freshwater Lake Washington watershed. The interpretive center explains the 1917 lock system and the salmon lifecycle.
The Coho salmon run peaks in September and October. You might see dozens of fish passing through the ladder windows on a good day.Booking tipFree admission. The fish ladder viewing area is open daily. Weekday mornings tend to be less crowded than weekends.
Explore the Ballard Farmers Market
food and drinkThe year-round Ballard Farmers Market on Ballard Avenue NW fills the street with 70+ vendors every Sunday. September is peak harvest, with stalls overflowing with stone fruit, tomatoes, peppers, apples, and chanterelle mushrooms from the Olympic Peninsula.
September is the single best month for variety. Summer crops overlap with early fall harvests, and you'll find produce that won't be available even 3 weeks later.Booking tipThe market runs 9am to 2pm every Sunday, rain or shine. Street parking fills fast, so consider biking the Burke-Gilman Trail.
Ride the ferry to Bainbridge Island
sightseeingThe 35-minute Washington State Ferry from Colman Dock at Pier 52 crosses Elliott Bay to Bainbridge Island. The ride itself gives you skyline views of downtown Seattle with Mount Rainier behind it, and Bainbridge's Winslow town center has wine tasting rooms, galleries, and waterfront walking trails.
September offers some of the clearest days of the year for skyline views from the water. The golden afternoon light on the return trip is worth timing around.Booking tipWalk-on passengers don't need reservations. If you're bringing a car, book ahead on the WSDOT ferry reservation system, especially on weekends.
Tour craft breweries in Ballard
food and drinkBallard has over 10 breweries within walking distance of each other, concentrated along NW 45th and 46th Streets and Leary Avenue NW. Reuben's Brews, Stoup Brewing, and Peddler Brewing are all within a few blocks. September is fresh-hop season, so each brewery tends to have at least one limited fresh-hop release on tap.
Fresh-hop beers are only available for a few weeks. The hops are brewed within 24 hours of harvest, and the resulting beer has a green, floral quality that fades quickly. This is a once-a-year window.Booking tipMost Ballard breweries don't take reservations. Weekday afternoons are the easiest time to find seating.
Walk the Washington Park Arboretum
natureThe 230-acre Arboretum stretches along the shore of Lake Washington between the University of Washington and Madison Park. Over 40,000 trees, shrubs, and vines from around the world fill the collection. The Japanese Garden near the south entrance was designed in 1960 by Juki Iida.
Early fall color begins in the vine maples and Japanese maples by mid-to-late September. The Arboretum is one of the first places in Seattle where you'll notice the shift.Booking tipThe Arboretum grounds are free and open dawn to dusk. The Japanese Garden charges a small admission fee and closes earlier, so check the seasonal hours.
Kayak on Lake Union
outdoor recreationLake Union sits in the middle of the city, surrounded by houseboats, Gas Works Park, and the South Lake Union tech campus. Rental outfitters along Westlake Avenue N provide single and tandem kayaks. On clear days, you can see the Space Needle, the Aurora Bridge, and Mount Rainier from the water.
September water temperatures on Lake Union hover around 18-19°C (64-66°F), still comfortable enough for a paddle. Summer crowds on the lake thin after Labor Day, and seaplane traffic from Kenmore Air is lighter.Booking tipWeekday morning rentals are typically available without advance booking. Weekend afternoons fill up, so reserve online the day before.
Visit the Museum of Pop Culture (MoPOP)
cultureMoPOP at Seattle Center sits beneath its Frank Gehry-designed exterior next to the Space Needle. The permanent collection covers the history of rock music, science fiction, and video games. The Nirvana and Jimi Hendrix exhibits are rooted in Seattle's music history, with original instruments, stage costumes, and handwritten lyrics.
MoPOP is a strong indoor backup for smoky or rainy September days. PAX West sometimes partners with MoPOP on gaming exhibits during the first week.Booking tipBuy tickets online to skip the line. Weekday visits are noticeably quieter than weekends.
What to eat in September
In season: fruit
Wild blackberries
Himalayan blackberries grow along practically every trail, fence line, and vacant lot in Seattle. By September they reach peak sweetness. Locals pick them freely along the Burke-Gilman Trail and in Discovery Park. The thorns are vicious, so long sleeves help.
Honeycrisp apples
Washington State grows more apples than any other state, and Honeycrisp harvest typically begins in September. The Ballard Farmers Market and University District Farmers Market carry them direct from orchards in the Wenatchee and Yakima valleys.
On menus now
Dungeness crab
The late-summer Dungeness season continues through September. You'll find it at Pike Place Market fish stalls and in crab rolls at waterfront restaurants along the Elliott Bay waterfront. The meat is sweet, briny, and firm.
What to drink
Fresh-hop IPA
Yakima Valley hops are harvested and delivered to Seattle breweries the same day. The resulting beers have a grassy, intensely floral quality that fades within weeks. Breweries in Ballard, Georgetown, and Fremont release new batches throughout September.
In markets
Chanterelle mushrooms
Golden chanterelles appear at farmers markets and on restaurant menus across the city in September, foraged from the damp forests of the Olympic Peninsula and Cascades. The earthy, peppery flavor pairs with Pacific Northwest salmon on menus across Capitol Hill and Wallingford.
Regular events in September
Bumbershoot
Seattle's long-running arts and music festival at Seattle Center has featured hundreds of musical acts, comedy shows, film screenings, and visual art installations over Labor Day weekend. The festival has shifted formats over the years, so check the current year's lineup and ticketing.
Labor Day weekend (late August to early September)Georgetown Trailer Park Mall Night MarketFree
Georgetown's warehouse district hosts an evening market on select September dates with vintage goods, local art, street food vendors, and live music. The industrial neighborhood south of downtown has a gritty charm that feels nothing like the tourist waterfront.
Select evenings in September (check schedule)Fremont Oktoberfest
Fremont's Oktoberfest fills several blocks of the self-proclaimed 'Center of the Universe' neighborhood with beer tents, bratwurst, live polka bands, and stein-holding competitions. Over 100 beers on tap, many from Pacific Northwest breweries.
Late SeptemberSeattle Art Fair
Galleries and art dealers from across the Pacific Northwest and beyond exhibit contemporary art at CenturyLink Field Event Center. The 4-day fair draws collectors, curators, and casual visitors. Satellite pop-up shows appear in Pioneer Square and Capitol Hill galleries during the same week.
Early to mid-September (varies by year)Best places this September
Pike Place Market
marketThe 9-acre public market along Pike Place has operated since 1907. In September, the farm tables carry peak-harvest produce, the flower stalls are dense with dahlias, and the post-Labor Day crowds are more manageable. The lower levels hold small shops and the original Starbucks location at 1912 Pike Place draws a steady line.
DowntownKerry Park
viewpointThis small park on the south slope of Queen Anne Hill is the classic Seattle skyline viewpoint, with the Space Needle, downtown towers, Elliott Bay, and Mount Rainier lined up in a single frame. On clear September evenings, the sunset behind the Olympic Mountains turns the sky pink behind the city.
Queen AnneDiscovery Park
parkSeattle's largest park covers 534 acres on the Magnolia bluff overlooking Puget Sound. The 2.8-mile Loop Trail passes through forest, meadows, sea cliffs, and the West Point Lighthouse. September's dry conditions make the bluff trails less muddy than any month from October through May.
MagnoliaChihuly Garden and Glass
museumDale Chihuly's permanent exhibition next to the Space Needle displays massive blown-glass sculptures in indoor galleries and an outdoor garden. The Glasshouse centerpiece is a 12m-long suspended sculpture in red, orange, and yellow. September afternoons cast warm light through the Glasshouse ceiling.
Seattle CenterCapitol Hill
neighborhoodSeattle's densest neighborhood for restaurants, bars, coffee shops, and independent retail. Pine and Pike Streets between Broadway and 12th Avenue form the main corridor. September evenings are still warm enough for patio dining, and the bar scene is active without the packed-out energy of summer weekends.
Capitol HillGas Works Park
parkThe rusted remains of the Seattle Gas Light Company plant sit on a hill above the north shore of Lake Union. The park offers skyline views across the water toward downtown and South Lake Union. Locals fly kites on the hill and watch seaplanes take off from the lake below. September afternoons here have a golden quality that makes the industrial ruins oddly photogenic.
WallingfordOlympic Sculpture Park
artThe Seattle Art Museum's free outdoor sculpture park stretches 9 acres along the Elliott Bay waterfront between Belltown and the grain terminal. Alexander Calder's 'Eagle' and Richard Serra's steel curves sit against a backdrop of Puget Sound and the Olympic Mountains. On clear September days, the mountain views from the park's upper terrace are some of the best in the city.
BelltownBallard Locks (Hiram M. Chittenden Locks)
landmarkThe Locks connect the saltwater of Puget Sound to the freshwater of Lake Union and Lake Washington. You can watch boats of all sizes rise and fall through the lock chambers, then walk to the fish ladder to see salmon migrating upstream. The Carl S. English Jr. Botanical Garden on the grounds is free and well-maintained.
Ballard
Your packing checklist
Tick items off as you pack. Your progress saves in this browser.
Insider tips
The Ballard Farmers Market on Sunday mornings is where locals actually shop. The Pike Place Market produce is good, but Ballard's vendors are more likely to be the farmers themselves. Get there by 10am for the best chanterelle selection.
If wildfire smoke rolls in, the Seattle Central Library on 4th Avenue is a striking piece of architecture by Rem Koolhaas and a comfortable place to spend a few hours. Free Wi-Fi, reading rooms with city views, and air filtration you can feel.
The water taxi from Pier 50 to West Seattle's Seacrest Dock takes about 10 minutes and gives you waterfront views of the skyline without the tourist markup of a harbor cruise. From Seacrest, it's a short walk to Alki Beach.
Fresh-hop beers sell out fast. If a brewery posts a new release on social media, go that day. Some kegs don't last 48 hours.
The Washington State Ferries to Bainbridge Island are less crowded on weekday afternoons, and the return trip east catches the sunset behind the Olympics. Walk on rather than drive to avoid the car-queue wait.
Avoid these mistakes
- Assuming September means guaranteed sunshine. The second half of the month can turn gray and drizzly with little warning. Pack rain gear even if the forecast looks clear on the day you arrive.
- Booking a downtown hotel during PAX West weekend (Labor Day) without realizing the convention fills 70,000+ attendees into a few blocks around the Washington State Convention Center. Rates spike and restaurants have long waits.
- Skipping layers because the afternoon is warm. A sunny 21°C afternoon at Pike Place Market can turn into a 13°C evening on the waterfront within a couple of hours, and the marine breeze off Elliott Bay adds wind chill.
- Planning an all-outdoor itinerary without indoor backup options. Wildfire smoke can arrive from Eastern Washington overnight and persist for days. Having a list of museums, breweries, and covered markets saves the trip.
- Driving everywhere instead of using transit. Link Light Rail connects the airport (SEA) to downtown, Capitol Hill, and the University District. The downtown core, Pike Place, and the waterfront are all walkable. Parking in Seattle is expensive and scarce.
Practical tips for September
September in Seattle doesn't require heavy planning, but a few practical details help. Book accommodation for mid-to-late September to dodge both Labor Day pricing and PAX West crowds downtown. The ORCA card works across buses, Link Light Rail, and the streetcar, and you can load it at any station. The King County Metro system covers most neighborhoods visitors care about, and the Link runs from SEA-Tac Airport to the University of Washington with stops at Capitol Hill and downtown. Check AirNow.gov every morning if you're planning outdoor activities, as wildfire smoke conditions can change overnight. Restaurants in Capitol Hill and Ballard don't typically require reservations on weeknights in September, but weekend dinner at popular spots still benefits from booking a day or two ahead. Ferry schedules shift after Labor Day from summer to fall timetables, so verify departure times on the WSDOT website before heading to Colman Dock.
FAQ
Is September a good time to visit Seattle?
September is one of the 3 best months to visit Seattle. You get the tail end of the dry season, with average highs of 21°C (70°F) and only about 50mm of rain across 7 days. Crowds thin after Labor Day, hotel rates drop from summer peaks, and the city has a relaxed energy. The main risk is wildfire smoke, which varies year to year.
How bad is wildfire smoke in Seattle in September?
It varies widely. Some Septembers are entirely clear, while others bring multiple days with AQI readings above 150 (unhealthy). The smoke drifts in from fires in Eastern Washington, Oregon, and Northern California. There's no reliable way to predict it more than about a week out. Monitor AirNow.gov in the days before your trip, and have indoor activities planned as backup.
What should I wear in Seattle in September?
Layers work best. Mornings start cool at 13°C (55°F) and afternoons warm to 21°C (70°F). A t-shirt with a fleece and a packable rain shell covers most situations. Comfortable walking shoes with grip matter because the hills and sidewalks can be slick when wet. Shorts are fine for sunny afternoons, but you'll want long pants by evening.
Is September rainy in Seattle?
September is one of the driest months, averaging about 50mm of rain across 7 days. Compare that to November's 169mm or December's 201mm. The rain that does fall tends to be a light drizzle rather than a heavy downpour. The second half of the month is wetter than the first, but even then, full-day rain is uncommon.
Are there any major events in Seattle in September?
PAX West, the largest gaming convention on the West Coast, fills the Washington State Convention Center over Labor Day weekend. Bumbershoot at Seattle Center has historically been a major arts and music festival around the same weekend. Fremont Oktoberfest brings beer tents and bratwurst to the Fremont neighborhood in late September. Fresh-hop beer season runs throughout the month at breweries across Ballard and Georgetown.
Things to Do in Seattle in September
Free cancellation Chef Guided Food Tour of Pike Place Market
City tour — 2 hours, free cancellation.
via Viator
Free cancellation Mt. Rainier National Park Highlights Tour
Outdoor experience — free cancellation.
via Viator
Free cancellation Seattle City Highlights Tour
City tour — 3 hours, free cancellation.
via Viator
Free cancellation Seattle's Original Guided Harbor Cruise
Cruise — 1 hour, free cancellation.
via Viator
Free cancellation Mt. Rainier Day Tour from Seattle
Day trip — free cancellation.
via Viator
Free cancellation Seattle City and Snoqualmie Falls Half-Day Guided Tour
Outdoor experience — 4 hours, free cancellation.
via ViatorLast verified by automated review (v1.7.2) on June 19, 2026. What is automated review?