Pacific Northwest
The Pacific Northwest is the jewel in the crown of the lower forty-eight states if you ask my opinion (subtle bias since I grew up there). The region is much more than drizzle, coffee, and mountains. I highly suggest anyone take the first chance they can to explore this beautiful region.
To avoid the rain, visiting between May and September is your best bet. The Northwest cities, Seattle, Vancouver, and Portland, are all unique to themselves and stunning in their own way. If you can, make sure you take time to escape to the coast or over the pass to Eastern Washington, Oregon, or Idaho.
Seattle
Being a fifth-generation Seattleite (a rarity in that part of the country), I've spent a substantial portion of my life visiting cities across the PNW. Starting in Seattle, this waterside city is beautiful. Please take your time enjoying Pike Place Market. Its quirky style and unique shops are quirky and fun. The lower levels of the Market are staples for the long-time Market goer. One tip of advice, never call it Pike's Market. It's a dead giveaway that you're a tourist. I recommend you take a ferry ride to Bremerton, visit the University of Washington campus (especially in spring when the cherry trees are blooming), and a stop at Kerry Park. For your night out, there's no better place than Capitol Hill. If you're heading north of downtown, Fremont and Ballard have pleasant little shopping districts, and if you can, make a trek out to Golden Gardens.
Vancouver
In my opinion, Vancouver is a touch of New York City, a sprinkle of British character, wrapped in Canadian charm and a lot of international energy. It's a really unique place to see if you're interested in modern architecture or international cuisine. With Whistler not far away, it's an obvious go-to for winter sports athletes and enthusiasts. I recommend driving up to Cypress Mountain for an incredible view of the city. Many have heard about Vancouver's Capilano Suspension Bridge, but I prefer the Lynn Canyon Suspension Bridge. It's not as long, but much less crowded and free! I also really like riding the little passenger ferries in False Creek. This is also a great way to get from downtown to Granville Market. Another highlight for me is a stop at Jericho Beach. Between the Public Tennis Courts and the sea, there are several bramble patches. Hundreds of bunny rabbits have made this bramble their home, and they are not afraid to eat an apple or carrot from your hand.
Portland
The Rose City is a place unlike any other. It's edgy, a bit gritty, and very green. My favorite parts of Portland are actually not downtown. I really like strolling the quirky shops along Hawthorne Blvd east of the Willamette River. When it comes to Portland, I highly suggest taking a day and driving to Hood River along the Columbia River. Known as the Columbia River Gorge, the drive is absolutely stunning. On the way, you need to check out Multnomah Falls. It's a sight to remember and an excellent location for a travel picture. Hood River, Oregon, is a bit more arid and perfect for wine growing. If you enjoy wine, this is a great place to go. The Oregon Coast is also exceptional, but I'll cover that in the nature section.
The East Side
Speaking of the arid climate, east of the Cascade Mountains is a place you should really consider visiting. Heading east from Seattle, you should consider stopping in Leavenworth, a Bavarian-themed city that is incredibly charming in the autumn and winter months. The North Cascade region of Washington State is almost like the old west with a very sparse population and rich natural beauty. If you're in this area, you should stop by Lake Chelan. The lake is beautiful and features a high-speed ferry to the remote village of Stehekin. Grand Coulee Dam isn't far away and is a true feat of engineering. It is the largest power station in the United States and features enough concrete to build a highway from Seattle to Miami.
My last two recommendations for the eastern side of the Pacific Northwest are Spokane and Coeur d'Alene. Spokane is the center of commerce for this region, and the Riverfront Park is excellent. Coeur d'Alene is stunning, the quintessential small American city amongst unrivaled nature. I also really like Walla-Walla, but it's a bit remote for most road trips, but if it's on your way, it's worth a stop. While Bend is the go-to eastern city in Oregon.
Nature
Now, there's no way I'm going to round out this page without talking about the natural beauty of the Pacific Northwest. From the ocean to mountain tops, the region is full of stunning sights. A trip to the West Coast isn't complete without checking out the Pacific Ocean. Washington and Oregon have great beaches, but the latter is better known for its rocky outcroppings and pristine sand. Spending some time in the mountains is also a must. Mount Hood and Rainier are easily accessible by car. I suggest spending some time at Mt. St. Helens as it's particularly fascinating to learn about the 1980 eruption and see the forest come back to life. If you're in the Seattle area, Puget Sound offers a beautiful respite from the hustle and bustle of the city.