During the 1997/98 El Nino event, a Northern Illinois University (NIU) faculty member and a group of undergraduate meteorology students interacted with the university's heating plant manager to determine whether climate information and forecast tools could assist him with NIU's natural gas purchase decisions each fall. Based on the El Nino-driven temperature forecasts and information developed by the faculty-directed student group, which indicated that northern Illinois would experience a warmer than average winter (December through March), the manager chose the option to ride the market on a continuous basis, buying incrementally to reduce total natural gas expenditures, rather than lock into a fixed price. To aid this annual decision process, winter El Nino–Southern Oscillation (ENSO) classifications, based on sea surface temperature (SST) data measured in the Nino-3 region, were analyzed to determine whether relationships existed between local mean winter temperature and the ENSO phenomena during the 1...