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

A 1/24 degree by 1/24 degree (~5 km) gridded data set consisting of monthly precipitation and temperature values for the conterminous U.S. was published as part of generating new division climate normals. The underlying data set is nClimGrid, and this is based on a set of station anomalies observed in any given month interpolated spatially using climate guidance and reconstructed into whole values. The resulting monthly grids are the equivalent of homogenous temperature and serially complete precipitation records. Therefore, a simple 30-year average of monthly grids from 1991-2020 yields directly a set of gridded climate normals. Monthly gridded climate normals are calculated for total precipitation, and maximum, minimum and average temperature.

A 1/24 degree by 1/24 degree (~5 km) gridded data set consisting of monthly precipitation and temperature values for the conterminous U.S. was published as part of generating new division climate normals. The underlying data set is nClimGrid, and this is based on a set of station anomalies observed in any given month interpolated spatially using climate guidance and reconstructed into whole values. The resulting monthly grids are the equivalent of homogenous temperature and serially complete precipitation records. Therefore, a simple 15-year average of monthly grids from 2006-2020 yields directly a set of gridded climate normals. Monthly gridded climate normals are calculated for total precipitation, and maximum, minimum and average temperature.

A 1/24 degree by 1/24 degree (~5 km) gridded data set consisting of monthly precipitation and temperature values for the conterminous U.S. was published as part of generating new division climate normals. The underlying data set is nClimGrid, and this is based on a set of station anomalies observed in any given month interpolated spatially using climate guidance and reconstructed into whole values. The resulting monthly grids are the equivalent of homogenous temperature and serially complete precipitation records. Therefore, a simple 100-year average of monthly grids from 1901-2000 yields directly a set of gridded climate baseline values. Monthly gridded climate baseline values are calculated for total precipitation, and maximum, minimum and average temperature.

The product referred to as nClimGrid-Daily is a set of daily gridded fields and area averages of temperature and precipitation that covers the Contiguous United States (CONUS) from 1951 to present and is updated daily. It is related to the monthly version of NClimGrid and NClimDiv, but with a daily temporal resolution. The gridded fields are stored in netCDF format with one file per data month. Area averages for nine types of regions are provided in CSV format with one file per region type and data month. At a resolution of approximately 0.0417 degrees latitude and longitude (nominally 5-km grid), the gridded data provide smoothed representations of the point observations. Since the accuracy of estimates for individual grid points and days can be sensitive to local spatial variability and the ability of the available observations and interpolation technique to capture that variability, the nClimGrid-Daily dataset is recommended for applications that require the aggregation of estimates in space and/or time, such as climate monitoring analyses at regional to national scales.

The NOAA Monthly U.S. Climate Gridded Dataset (NClimGrid) consists of four climate variables derived from the GHCN-D dataset: maximum temperature, minimum temperature, average temperature and precipitation. Each file provides monthly values in a 5x5 lat/lon grid for the Continental United States. Data is available from 1895 to the present. On an annual basis, approximately one year of "final" nClimGrid will be submitted to replace the initially supplied "preliminary" data for the same time period. Users should be sure to ascertain which level of data is required for their research.

The U.S. Daily Climate Normals for 1981 to 2010 are 30-year averages of meteorological parameters for thousands of U.S. stations located across the 50 states, as well as U.S. territories, commonwealths, the Compact of Free Association nations, and one station in Canada. NOAA Climate Normals are a large suite of data products that provide users with many tools to understand typical climate conditions for thousands of locations across the United States. As many NWS stations as possible are used, including those from the NWS Cooperative Observer Program (COOP) Network as well as some additional stations that have a Weather Bureau Army-Navy (WBAN) station identification number, including stations from the Climate Reference Network (CRN). The comprehensive U.S. Climate Normals dataset includes various derived products including daily air temperature normals (including maximum and minimum temperature normal, heating and cooling degree day normal, and others), precipitation normals (including snowfall and snow depth, percentiles, frequencies and other), and hourly normals (all normal derived from hourly data including temperature, dew point, heat index, wind chill, wind, cloudiness, heating and cooling degree hours, pressure normals). Users can access the data either by product or by station. Included in the dataset is extensive documentation to describe station metadata, filename descriptions, and methodology of producing the data. All data utilized in the computation of the 1981-2010 Climate Normals were taken from the ISD Lite (a subset of derived Integrated Surface Data), the Global Historical Climatology Network-Daily dataset, and standardized monthly temperature data (COOP). These source datasets (including intermediate datasets used in the computation of products) are also archived at the NOAA NCDC.

The U.S. Daily Climate Normals for 1981 to 2010 are 30-year averages of meteorological parameters for thousands of U.S. stations located across the 50 states, as well as U.S. territories, commonwealths, the Compact of Free Association nations, and one station in Canada. NOAA Climate Normals are a large suite of data products that provide users with many tools to understand typical climate conditions for thousands of locations across the United States. As many NWS stations as possible are used, including those from the NWS Cooperative Observer Program (COOP) Network as well as some additional stations that have a Weather Bureau Army-Navy (WBAN) station identification number, including stations from the Climate Reference Network (CRN). The comprehensive U.S. Climate Normals dataset includes various derived products including daily air temperature normals (including maximum and minimum temperature normal, heating and cooling degree day normal, and others), precipitation normals (including snowfall and snow depth, percentiles, frequencies and other), and hourly normals (all normal derived from hourly data including temperature, dew point, heat index, wind chill, wind, cloudiness, heating and cooling degree hours, pressure normals). Users can access the data either by product or by station. Included in the dataset is extensive documentation to describe station metadata, filename descriptions, and methodology of producing the data. All data utilized in the computation of the 1981-2010 Climate Normals were taken from the ISD Lite (a subset of derived Integrated Surface Data), the Global Historical Climatology Network-Daily dataset, and standardized monthly temperature data (COOP). These source datasets (including intermediate datasets used in the computation of products) are also archived at the NOAA NCDC.