Volunteer Weather Observers around Wisconsin
UW Soil Science
These weather data are maximum and minimum air temperature and precipitation, for the
previous 24 hours, observed at about 7 am. The observations are made by a group of about 60
volunteers, who immediately transmit them to the National Weather Service Forecast Office in
Sullivan, WI. Meteorologists there collect the readings and make them available on the Weather
Service's computer system. We retrieve the data from McIDAS, a system created and maintained
by the Space Science and Engineering Center of the University of Wisconsin-Madison. Until December 2003, the
reports were referred to by the NWS as "OPU", for "Other Public Products"; they are now officially "HYD", for "hydrometeorological data".
Some of the observers providing these measurements are part of the National Weather Service's
Cooperative Observation Program, and their data will be included in long-term records. Other
observers are not official members of the Cooperative Program, and use their own equipment.
Thus, averages published in the "Climate of Wisconsin" (about 8 months from now) may not agree
with those derived from the daily summaries here.