diff --git a/var/spack/repos/builtin/packages/netcdf-cxx4/package.py b/var/spack/repos/builtin/packages/netcdf-cxx4/package.py
index a31e43c879a..d11bc4ea414 100644
--- a/var/spack/repos/builtin/packages/netcdf-cxx4/package.py
+++ b/var/spack/repos/builtin/packages/netcdf-cxx4/package.py
@@ -58,6 +58,7 @@ def libs(self):
         )
 
     def configure_args(self):
+        config_args = []
 
         if '+static' in self.spec:
             config_args.append('--enable-static')