You could avoid writing the NetCDF file altogether and just use arcpy.NumPyArrayToRaster
to bring your numpy array of mean precip directly into ArcMap. The code could look someting like this:
import arcpy
xyOrig = arcpy.Point(float(lonmin),float(latmin))
arcpy.workspace = "C:\\workspace"
arcpy.env.overwriteOutput = True
rasterName = "traster"
outRaster = os.path.normpath(os.path.join(arcpy.workspace,rasterName))
grid1=arcpy.NumPyArrayToRaster(z,xyOrig,dx,dy)
grid1.save(os.path.join(arcpy.workspace,outRaster))
strPrj = "GEOGCS['GCS_WGS_1984',DATUM['D_WGS_1984',SPHEROID"\
"['WGS_1984',6378137.0,298.257223563]],PRIMEM['Greenwich',0.0],"\
"UNIT['Degree',0.0174532925199433]]"
arcpy.DefineProjection_management(outRaster,strPrj)
print "Written: %s" % grid1
arcpy.AddMessage("Written: %s" % grid1)
The full example from which this snippet was obtained is here:
dap2raster.py
BTW, when I need to write NetCDF, I use the NetCDF4-Python library as it can read and write NetCDF4 files and read from OPeNDAP in addition to reading and writing NetCDF3 files. It's nice to use a common interface for all. And you can get a 32-bit windows version of NetCDF4-Python compatible with ArcGIS 10.0+ at Gohlke's Python Binaries for Windows site
Good luck!
I just tested this using ArcGIS for Desktop 10.2 and was able to convert a BIL file downloaded from FEWSNET to a GRID format using the Raster To Other Format (Conversion) tool.
I downloaded and unzipped the ZIP file to find the BIL file, then opened the tool.
I chose the BIL file as my Input Raster, and set the Output Workspace to a folder where I had write access (C:\temp) and the Raster Format (for output) to GRID.
Best Answer
You might try the Raster to netCDF tool in ArcView.