GHCN Processor is a command-line tool that reads temperature data from the Global Historical Climatic Network (GHCN) database and produces an annual or monthly temperature series in CSV format for an arbitrary set of stations. Stations are filtered based on a simple EL expression passed to the tool. For example, you can select only stations that are in the Northern Hemisphere, in hilly and rural locations. You can also select stations that started reporting in a given year, and so on. The tool supports more than one method of grid partitioning, station combination, and can use both the adjusted data and raw unadjusted data.