U.S. Daily Gridded Precipitation and Temperature Climate Normals for 1991-2020 (NCEI Accession 0259962)

The U.S. Daily Gridded Climate Normals Datasets are derived from the nClimGrid-Daily Dataset newly produced by the NOAA National Centers for Environmental Information (NOAA NCEI). Climatologically aided interpolation was used to transform an extensive set of station temperature and precipitation values into grids at a high spatial resolution of 1/24° latitude/longitude, or approximately 5 km. The values for each individual grid cell change smoothly from day-to-day through the application of the same methods used to generate daily normals for observation stations. The averages of all daily gridded temperature normals are constrained by a harmonic fit to equal the monthly gridded. A moving window averaging technique is used to generate smooth daily gridded precipitation normals which are then also adjusted by month so that the sum of the days would equal the monthly gridded normals. Daily gridded climate normals are calculated for total precipitation, and maximum, minimum and average temperature for the conterminous U.S