The most likely reason for your problem is air infiltration. Cold air in entering thru penetration, making the surface cold, allowing interior air (warmer air carries more moister) to cool & condense.
1/ Sealing leaks. If your seeing the moister @ the baseboard, it's probably leaky Where the wall meets the floor. Caulking may cure.
2/ If air in coming in, it also has to go out. Weatherization measures should be done on whole house. Look for a major air draw from the attic. If your in a Snow climate, look for signs of heat-loss (Snow melting or ice build-up)