The Northwestern region includes the states of Idaho, Montana, Oregon, Washington and Wyoming. January is cool and wet for the coastal sections of the Northwestern region. It is cooler but drier away from the coast. The Pacific coast stays damp as moisture comes from the Pacific Ocean.
Higher elevations are much colder and get a lot of snow.
The Pacific Ocean is cooler than the land, so it doesn't provide hot humid air like other regions. It actually makes it cooler along the coast than inland. July is a sunny month for the northwest. The coldest recorded temperature is - 70 degrees Fahrenheit in Rodgers Pass, Montana on January 20, 1954. For more climate data, look at the Weather Research Center site.