Hourly Precipitation Data - Special ASOS Network is a digital data set archived as DSI-3241 at the National Climatic Data Center (NCDC). The data were recorded on paper charts by the Universal Rain Gauge, which is an older type of rain measuring device. This gauge has a pen arm that continuously scribes a line on a chart that is mounted on a rotating drum. The position of the line corresponds to ... the weight of the contents of the gauge holding bucket. The gauge has a 0.01 inch resolution. DSI-3241 data is from US first order Automated Surface Observing System (ASOS) stations, but are separate from ASOS observations; and the earliest data at a station generally coincide with conversion to ASOS. The earliest data is May 1995. The National Weather Service has continued to fund the operating expenses of Universal Rain gauges at about 150 first order stations that are now ASOS. All stations are located in the 48 contiguous states of the United States, plus Alaska. This data will continue to be available as long as funding continues. Some stations have sent data sporadically. Only partial data may be available for a given data month. No data for the July 1995 data month is available.