Wet garments in contact with the skin cause twenty five times more heat loss than dry ones. The next layer should trap warm air next to the body. Several light layers that can be added or deleted for changing conditions makes it easier to regulate your body temperature. Several thin layers are generally warmer than one thick layer. The final layer is a shell to protect your first two layers from rain and from wind, which can cause heat to be drawn away at a dangerous rate.
Wind chill is the effect of wind on wet skin.
Sleeping Warm Your sleeping bag should be lightweight, warm comfortable, and easily compressible and good for year around camping in Western Washington. A good three-season bag should fit this requirement. There are several types of insulation available. They are very compressible, retain their loft well and are well built and last a long time if properly cared for. They are very expensive and if they get wet they take a long time to dry out.