Herbs have their own set of growing requirements that depend on just what kind of herb they are. An annual like basil will grow anywhere as long as it has some good soil, moisture, no frost and about 3 months of growing time at 65 degrees or more. The same applies to other herbs with their requirements. So to find out what to grow in the Northwest, we simply need to find out what the growing conditions are and then list the appropriate plants. It is usually wise to start with the most popular herbs and then if successful, you can branch out with new ones.
One of the most obvious characteristics of the Northwest is the shorter growing season. This means a delayed spring. In other areas where the planting is getting started, your latitude is still experiencing frosty nights. Then in the fall, you get an earlier freeze, marking the end of gardening. Since herbs don't fruit, they don't need a set amount of growing time, unless you are starting new annual herbs, like basil, cilantro, parsley which you can start indoors under growing lights about six weeks before planting dates.
Cooler summertime temperatures are another notable characteristic of the Northwest. The air off the Pacific Ocean brings moisture and cool air. This means you can easily grow the perennial herbs like mints which thrive under these conditions. Plants like rosemary and sage might have a harder time since they thrive under a hot and sunny environment.
The Northwest is also known for its vast areas of evergreen forests. Whenever you have forest, you have acid soil. Instead of trying to find the few herbs that like acid soil, you can build a raised bed garden and make a rich loamy soil that most herbs will thrive in with a pH closer to 6.5 and 7. This is also a way to overcome rocky soil problems. Herbs like basil, dill, parsley, oregano, thyme, cilantro, chives and lemonbalm will thrive in a raised bed with the moist air and cool evenings.