This data release (DR) is the update of the U.S. Geological Survey - ScienceBase data release by Bera (2024), with the processed data through September 30, 2024. The primary data for water year 2024 (a water year is the 12-month period, October 1 through September 30, in which it ends) is downloaded from ANL website (Argonne National Laboratory, 2025) and is processed following the guidelines documented in Over and others (2010). Processed WY24 data are appended to update the Watershed Data Management (WDM) database file ARGN23.WDM (Bera, 2024), which was then renamed as ARGN24.WDM. Daily potential evapotranspiration (PET) was computed from average daily air temperature, average daily dewpoint temperature, daily total wind speed, and daily total solar radiation and disaggregated to hourly PET, in thousandths of an inch, using the Fortran program LXPET (Murphy, 2005) for the period 10/01/2023 – 09/30/2024. This DR also describes the Watershed Data Management (WDM) database file ARGN24.WDM. ARGN24.WDM file contains nine data series: air temperature, in degrees Fahrenheit (dsn 400), dewpoint temperature, in degrees Fahrenheit (dsn 500), wind speed, in miles per hour (dsn 300), solar radiation, in Langleys (dsn 600), computed potential evapotranspiration, in thousandths of an inch (dsn 200), and four data-source flag series: for air temperature (dsn 410), dewpoint temperature (dsn 510), wind speed (dsn 310), and solar radiation (dsn 610), respectively, from January 1,1948, to September 30, 2024. Missing and apparently erroneous data values were replaced with adjusted values from nearby weather stations used as “backup.” The Illinois Climate Network (Water and Atmospheric Resources Monitoring Program, 2025) station at St. Charles, Illinois, was used as "backup" for the hourly air temperature, solar radiation, and wind speed data. The Midwestern Regional Climate Center (Midwestern Regional Climate Center, 2025) provided the hourly dewpoint temperature and wind speed data collected by the National Weather Service from the station at O'Hare International Airport and used as "backup." Each data source flag is of the form "xyz", which allows the user to determine its source and the methods used to process the data (Over and others, 2010). This DR provides WDM file ARGN24.WDM and the following tab-delimited text files, each with data from January 1, 1948, to September 30, 2024: "Air_temperature.txt" contains hourly air temperature data in degrees Fahrenheit and associated data-source flags. "Dewpoint_temperature.txt" contains hourly dewpoint temperature data in degrees Fahrenheit and associated data-source flags. "Solar_radiation.txt" contains hourly solar radiation data in Langleys and associated data-source flags. "Wind_speed.txt" contains hourly wind speed data in miles per hour and associated data-source flags. "PET.txt" contains hourly PET data, in thousandths of an inch. Tab-delimited text files can be opened with any text editor or Microsoft Excel. To open the WDM file user needs to use the SARA Timeseries utility executable file attached in this page. References Cited: Argonne National Laboratory, 2025, Meteorological data, accessed on February 18, 2025, at https://www.atmos.anl.gov/ANLMET/numeric/. Bera, M., 2024, Meteorological Database, Argonne National Laboratory, Illinois, January 1, 1948 - September 30, 2023: U.S. Geological Survey data release, https://doi.org/10.5066/P146RBHK. Midwestern Regional Climate Center, 2025, Meteorological data, accessed on February 19, 2025, at https://mrcc.purdue.edu/CLIMATE/. Murphy, E.A., 2005, Comparison of potential evapotranspiration calculated by the LXPET (Lamoreux Potential Evapotranspiration) Program and by the WDMUtil (Watershed Data Management Utility) Program: U.S. Geological Survey Open-File Report 2005-1020, 20 p., https://pubs.er.usgs.gov/publication/ofr20051020. Over, T.M., Price, T.H., and Ishii, A.L., 2010, Development and analysis of a meteorological database, Argonne National Laboratory, Illinois: U.S. Geological Survey Open-File Report 2010-1220, 67 p., http://pubs.usgs.gov/of/2010/1220/. Water and Atmospheric Resources Monitoring Program, Illinois Climate Network, 2025, Illinois State Water Survey, 2204 Griffith Drive, Champaign, IL 61820-7495. Data accessed on January 9, 2025, at http://dx.doi.org/10.13012/J8MW2F2Q.