NARCCAP data is CF-compliant, and therefore can be imported directly into ArcGIS v.9.3 or higher. There are two ways to import NetCDF data: as a feature layer, or as a raster layer. NOTE: By default, each data point is drawn using the same symbol. To apply a color ramp to the points, right-click the layer name and choose Properties, click the Symbology tab, and choose Quantities->,Graduated Colors. (screenshot) Information about the size of the timestep and the starting point of each file can be found in the headers of the NetCDF file. On Windows, you can use a program like Panoply to view NetCDF header information. Specifying the timestep by index is inconvenient, but necessary if the file contains more than 200 timesteps. If you need to work extensively with time (subsetting, averaging, or concatenating the time dimension), you will likely find it easier and get better performance using other tools to process the NetCDF files before importing them into GIS. In particular, the NCO toolkit, when compiled with udunits support, allows you to work with times and dates instead of index values, and the CDO toolkit implements a number of important climatological averages. If the file has 200 or fewer timesteps (i.e., if you were able to select the timestep from a dropdown list), then after the data has been displayed in ArcMap, you can change the timestep through Layer Properties: If you are having problems overlaying the NARCCAP data onto other datasets, you may have a projection problem. All projection problems have been fixed in ArcGIS 9.3, but here are some steps you can take to fix them if you are using an earlier version: Source.