Results of measurements are presented of clear-sky day solar UV irradiance (295--385 nm) in the August 1995 to June 1999 period at the Observatorio Astron¿mico de Rosario, Argentina, a place typical of the most populated Humid Pampa region of the country. The data give a detailed description of UV variation as a function of time in a given day and for different days of the year. Model calculations for clear-sky days at noon are done, employing the tropospheric ultraviolet visible radiation model (TUV) Madronich radiative transfer code, with the mean monthly ozone and aerosol content of the atmosphere and surface reflectivity provided by the Total Ozone Mapping Spectrometer (TOMS)/NASA instrument on board of the Earth Probe satellite. Two aerosol characteristics are tested in the model, rural-urban and mean urban, with the mean urban giving best agreement with the measurements. A simple mathematical expression is proposed for the mean typical curve, which gives a good approximation to the clear sky UV noon data for Rosario. It can be used for extending the results to nearby places and for comparison with other regions of the world having similar atmospheric and albedo conditions.