The document discusses different types of stations and networks used for climate observation in the US. It describes 4 major networks operated by NOAA: 1) local climatological data stations that define climate for 275 cities and towns, 2) the co-op network that establishes baseline climate using 5,200 temperature and 7,400 precipitation stations, 3) the hourly precipitation data network of 3,000 stations for hydrologic records, and 4) the historical climate network of 1,215 stations for documenting climate variations.