Pacific Northwest

I am guessing that the places you meant in your post were Olympic National Park and the Columbia River Gorge. I would avoid Labor Day if you can. Fall is often a great time weather wise and late Sept into October would be fine.

After Labor Day I wouldn't worry about crowds, at least in Oregon and Washington. A two-week road trip from SF to Seattle would give you time to see a lot west of the Cascades. If by "Columbia Valley" you mean the eastern part of WA, where the Columbia River circles down from Canada, you might be trying to do too much. If you mean the Columbia Gorge, where the river cuts westbound through the Cascades on its way to the ocean, that's an easy day trip out of the Portland area and back.

September weather is generally pretty good. Late September into October will have shorter days, cooler nights, and more chance of rain. The real risk is wildfire smoke, which has been an issue for the last several years and is most likely late in the summer. The fire could be in CA or BC but we could still get the smoke. No way to predict this with any precision so I'd say go ahead and keep planning.

Sorry, the post was late after a frazzled day of babysitting my grandson. Yes, we are planning on 2-3 days in Olympic National Forest area, including a ferry over to Victoria to spend a bit of time there. And also Columbia River Gorge and some waterfall chasing. Also want to spend a couple days up in Vancouver, Canada and a couple days in Seattle. Looks like maybe last week in September and first week in October will work, we’ll be taking a serious raincoat for sure just in case. From what I see, temps will be still pretty moderate.

After visiting Olympic National Park, take the Black Ball Ferry (MV Coho) from Port Angeles to Victoria. After your time in Victoria, take the BC ferry from Sydney to Tswassen to see Vancouver. Then drive down Interstate 5 for your time in Seattle.

Post-Labor Day is a great time to visit the PNW, if no wildfires are underway. As Dick noted there is no way to know about that until it happens though. Weather is typically mild the farther in to September you get. October is often quite lovely on the Oregon coast, though it's about the time some businesses start reducing hours (often closed Sun-Mon-Tues). Check the ferry schedule Port Angeles-Victoria and make reservations to be sure you get on (they reduce schedules in the fall) and pay attention to the time you have to arrive ahead (usually about an hour with a car).

Note that from May 24-Sept. 2 you must reserve a time slot to visit Multnomah Falls in the Columbia River Gorge. If you're waterfall chasing, there are many other choices besides there, many of us local folk would be happy to suggest alternatives. Depending on your route and interests would be happy to suggest places to visit.

By Sept waterfalls will be at their lowest water flow, barring some unusual heavy dump of rain.

Are you using your personal car or a rental car? If a rental that you pickup in Calif., be sure it is permitted to take it to Canada.

In any event be aware that BC auto law is pure no-fault.

That means you cannot recover from the at fault driver.
(e.g., you are stopped at a red light and get hit from behind. The driver that hit you does not pay for the damage.
You/your insurance pays for your car repair costs and you pay for your medical bills. If you have a $500 collision deductible it comes out of your pocket.)

More info here-- https://www.lexology.com/library/detail.aspx?g=3985bbad-58f6-4bc9-ab2a-c717e1cc8f02

With the start of school just after Labor Day, crowds drop significantly after the holiday.

After about Columbus Day, the Western Washington weather can be quite 'random'. The later into Oct., the cooler and wetter it becomes.

There are always wildfires in the PNW in Sept. The only question is where? So what I suggest is to be flexible with your plans so you can still have your vacation but avoid areas with heavy smoke. Sometimes the air quality is the worst worldwide. The PNW is a wonderful place to live and visit! I hope you have a good vacation!

My last visit to the area was a 7-night road trip in northern Oregon 2nd week in October 2021. Astoria, south along the coast, then inland via Salem to The Dalles and along the Columbia to Portland. We were very happy we'd booked all our rooms in advance. Everywhere was pretty crowded. I'd expect Labor Day weekend to be especially crowded in SF and north along the California coast.

cardfansip,
Just curious...if you are flying into San Francisco, how many days do you plan on taking to drive to Oregon? San Francisco, although considered Northern California, is actually closer to the middle of California in a north-south orientation. You would definitely want to stop somewhere overnight, unless you plan on a long day on the interstate. In which case, why San Francisco? If, however, you want to see some of the beautiful coast (redwood forests, dramatic coastlines, etc.), plan on driving Hwy 101. That will mean going slower and definitely taking two days to reach the Oregon border.

Just to clarify--there is Olympic National Forest, which surrounds Olympic National Park, so somewhat different jurisdictions. Be aware that the Hoh Rain Forest gets quite the crowds in the summer. Sept may be somewhat better. It is the most visited part of the park, along with the Hurricane Ridge viewpoint (day lodge burned down and is being rebuilt). Olympic National Park consists of the mountain area, and the coastal beach strip. The Olympic Mountains are spectacular, and the ocean section is a stunning and wildlife-rich seascape. ONP is my favorite national park in Washington, but helps to get into the backcountry. Columbia Gorge has many outings opportunities on both the WA and OR sides, though the waterfall area is more the OR side. Yes, as others have said the Aug-Sept time period has become difficult due to climate change--forest fires and what we are now calling "smoke season." Varies from year to year but we have begun to brace for it each year. Historically the fires tended to be in the Cascades and the east side of the state, though lately fires have been erupting in the Olympics as well. Our Octobers used to be cooler and the start of the rain, but not so much anymore.

If you decide to travel between Victoria (Swartz Bay) and Vancouver (Tsawwassen) by ferry - please be sure to make a reservation if you are driving. Record traffic levels this year. Visit bcferries dot com.

Judy,
Yes, we do plan on stopping along the way. We are looking at 3 days along the coast in Cali, then another 3 days across Oregon. The remainder in Washington including 3 days in the Olympia Forest and Park area and a night in Victoria, then heading to Seattle and Vancouver at the end. Total 16 days, I know we are doing a lot but lots of world to see so not sure when we will be back. We want to travel to Switzerland next year, soooo looking forward to that.

cardfansip,
So happy to hear you will spend a couple of days heading into Oregon. The coast north of SF is beautiful. Of all there is to see, I suggest a stay in Mendocino, perhaps arriving from there by way of Hwy 128 from the wine country around Sonoma, then up along the coast through some of the redwood state and national parks. Prairie Creek State Park is especially lovely, with a fern canyon that makes you feel you are in a prehistoric age. Check with AAA or Ca Tourist Bureau for maps, etc. And the coastal beauty continues into Oregon and up to Washington. The road along the Pacific Coast is one, big, magnificent journey! We have made the drive often and, to be honest, I get antsy for the NorCal road trip every year, although we can't always go every year. (Also, if you are a shell collector, the beaches in Oregon seem to have more than the beaches in California. Just be sure you don't pick them up where it is forbidden.)
Oh yes, the Quinalt Rain Forest is part of the Olympic Natl. Park and Pacific Natl. Forest. It is super!
I hope you have a great time. in the PNW!

Oops! I meant Olympic Natl. Forest, not Pacfic!

As others have said, Olympic National Park in September is a good time to go. I was there at the end of September a couple years ago and it was beautiful. Cool during the day for perfect hiking weather, but not too cold at night yet. Still lots of good light and not crowded. Hoh rainforest was the only place it got busy but going early enough made parking easy enough and even later it still wasn’t too bad. (But before 10 is still better- say 9 or so?) . The rest of the area was fine. Even Sol Duc, which is a beautiful trail to a waterfall, was no problem.

“The remainder in Washington including 3 days in the Olympia Forest and Park area and a night in Victoria, then heading to Seattle and Vancouver at the end. “

This last journey does not make sense.
Victoria is on an Island, a ferry ride away either from Vancouver or from Wash. State.
To see all those places, perhaps get up to Vancouver first, then the ferry across to Victoria, then another ferry back to Washington to make it a circular non backtracking trip.
You absolutely need timed and dated ferry reservations for all of them.
To go all the way across to Victoria for one day …..you won’t see much there.
Plan to stay at least three nights.

To go all the way across to Victoria for one day …..you won’t see much there.
Plan to stay at least three nights.

That would be wonderful if one has the time. I did a day trip to Victoria several years ago. Maybe I didn't see everything, but I saw a lot - the harbor front and the Empress Hotel, the Royal BC Museum, the capitol buildings, the park with the totem poles, had a nice lunch and visited Butchart Gardens. At the time I actually had friends living in Nanaimo but, needless to say, didn't get up there to see them. Not everyone has the time for 3 nights in a place and not everyone needs to see a lot to get a taste of a place. You see what you can see in the time you have. I definitely think it's worth the ferry over for the day (or 1 overnight) if that's what you have. I do still hope to get back there someday for a couple of nights at least.

And as an aside, I think October is the best month here in Oregon where I live. After labor day the places on the coast will still be crowded and hwy 101 will still be a parade of RV's but usually just really bad on the weekends. If you can drive the Oregon coast during the week in October it can be spectacular and not too crowded. On the other hand, if you can manage to hit Astoria on a Sunday they have the best farmers/craft market on the coast. And if you like fish & chips and don't mind standing in line a while try the Bowpicker - it's an institution and has the best f&c I've had. https://bowpicker.com/

Here's the website for the Black Ball Ferry Line that runs between Port Angeles WA and Victoria BC (on Vancouver Island). Here's the website for BC Ferries, a network that includes service between Swartz Bay (a little north of Victoria) and Tsawassen (south of the city of Vancouver on the mainland). An alternative route in BC would be from Nanaimo, farther north of Victoria on the island, to Horseshoe Bay, just north of the city of Vancouver. With a car you could do either.

In case you decide not to visit Vancouver, here's the Washington State Ferries website to get you from the Olympic Peninsula (where Olympic National Park is) to Seattle. You may find that your timeframe requires too much driving and not enough stopping and seeing the very many beautiful places your route takes you. If you decide to chop off the north end of the trip, you could leave your car in Port Angeles, take the Coho (the ship run by Black Ball) to Victoria as walk-on passengers (no reservation needed) for just a day or overnight in Victoria, then return to Port Angeles and drive to Seattle using one of the WA ferries. Vancouver is a wonderful city but possibly "a bridge too far" for the time you have and the distance you want to cover.

Thanks for all the information on this area, it is my first visit to the northwest. We are definitely overnighting in Victoria, at least for one full day and over nite. Re-thinking the Vancouver/Seattle end of trip Ferrying direct from Vancouver Island to Vancouver city makes some sense. I guess I was a bit nervous about locking in two timed ferry trips and the 3 1/2 hour length from the island to the city. I need to decide whether to cut Vancouver and just spend more time in Victoria and Vancouver island.
This whole segment of the trip brings up another question. I have read that some rental car companies restrict their rentals from going into Canada. Typically we reserve online well ahead of the trip. Are there particular rental companies that this is not an issue with?
Again, thanks for the info, advice and critique.

A Budget Rent a Car , via Costco, has this advisory:

Vehicles at this location can be driven throughout the continental U.S. with no restrictions. Based on availability, one-way rentals may be allowed to some U.S. cities.
Canada: Vehicles may be driven into Canada with no restrictions. The rental counter must be notified at the time of the rental that you plan to drive into Canada so the location can provide a copy of the "Canadian Non-Resident Insurance Card" or you may download the card here (provided at no cost). Based on availability, one-way rentals may be allowed to some Canada cities. . Mexico: Vehicles rented at this location are not allowed to travel into Mexico.

I used SFO as the pickup location

It's worth going to Portland just for the food! The Oregon coast is really nice, the California coast road HWY101 is something I love but most people would find it a pain; to slow and too curvy. October is fine in our neck of the woods, leaving after the music festival sounds like a better option to me. J

Should have said HWY 1 not 101, sorry