A new quality assurance system was developed and implemented operationally. The system uses rules-based GIS technology to fully automate spatial quality assurance of observed daily temperature values. This system uses gridded fields derived from quality controlled ASOS/AWOS hourly and daily temperature values as a ground truth to quality assure the cooperative network daily temperature data. This automated temperature validation (TempVal) system replaces the interactive Graphical Edit Analysis (GEA) temperature validation system that was approximately 70% automated and 30% manual and in use since the early 1990’s. Parallel tests of the old and new systems were made using regression analysis. Manual comparisons between the systems using outliers exceeding a pre-described threshold were performed. The results of the tests will be shown. Higher confidence in TempVal is attributed to a change in methodology (using grid fields) and access to higher quality data for use as “ground truth”. The GEA methodology derives a 3-sigma mean value using neighboring stations to quality assure a flagged data value. Additionally, TempVal is able to estimate daily replacement temperatures for any number of missing days whereas the GEA system can only generate temperature values under certain conditions.