This paper describes the ATEC repository of atmospheric data (ARAD) developed for the ATEC Four-Dimensional Weather (4DWX) system and gives examples of its operational uses at Dugway Proving Ground's West Desert Test Center (WDTC). The ARAD is a relational database developed by WDTC in collaboration with the National Center for Atmospheric Research (NCAR). One use of climatological data at Army test ranges is to help determine the best times to schedule field tests (e.g., artillery firings and missile launches). Many of these tests require specific atmospheric conditions. Prior to development of the ARAD, only simple climatological analyses using the range surface observations were practical. The ARAD allows the use of many other data sets (e.g. rawinsonde, wind profiler, and RAWS) in developing complex climatologies utilizing multiple data sets.