I have noticed that in really wet weather (moved to Vancouver recently), my 2002 Hyundai Accent GSI starts to smell bad (like wet carpet). Upon inspection, the back seats feel damp to touch and when I lift up the trunk mat, there is water pooling around the spare tire. Any idea where/how the water might be getting in?

Check the trunk rubber for damage and/or improper mounting. There will ordinarily be drain holes in the area where the tail light assemblies mount to the back of the car. If they are plugged up, the water will have nowhere to go when it rains, and will seep through the gasket between the tail light housings and the body metal. If unable to find the problem, have someone soak the back of the car in the trunk / tail light area with a garden hose, and watch for water intrusion from inside the trunk with a flashlight (hopefully, the rear seat backs flip down so you can gain access to the trunk from inside the car). Good luck!