diff --git a/internal_tests/pytests/grid_stat/test_grid_stat_wrapper.py b/internal_tests/pytests/grid_stat/test_grid_stat_wrapper.py
index 017731ed7..239991bd7 100644
--- a/internal_tests/pytests/grid_stat/test_grid_stat_wrapper.py
+++ b/internal_tests/pytests/grid_stat/test_grid_stat_wrapper.py
@@ -484,6 +484,9 @@ def test_handle_climo_file_variables(metplus_config, config_overrides,
         ({'GRID_STAT_CLIMO_MEAN_HOUR_INTERVAL': '12', },
          {'METPLUS_CLIMO_MEAN_DICT': 'climo_mean = {hour_interval = 12;}'}),
 
+        ({'GRID_STAT_CLIMO_MEAN_HOUR_INTERVAL': 'NA', },
+         {'METPLUS_CLIMO_MEAN_DICT': 'climo_mean = {hour_interval = NA;}'}),
+
         ({
              'GRID_STAT_CLIMO_MEAN_FILE_NAME': '/some/climo_mean/file.txt',
              'GRID_STAT_CLIMO_MEAN_FIELD': '{name="CLM_NAME"; level="(0,0,*,*)";}',
diff --git a/metplus/wrappers/command_builder.py b/metplus/wrappers/command_builder.py
index dc834c840..4e05afd56 100755
--- a/metplus/wrappers/command_builder.py
+++ b/metplus/wrappers/command_builder.py
@@ -1500,7 +1500,7 @@ def handle_climo_dict(self):
             'time_interp_method': ('string', 'remove_quotes,uppercase'),
             'match_month': ('bool', 'uppercase'),
             'day_interval': ('string', 'remove_quotes,uppercase'),
-            'hour_interval': 'int',
+            'hour_interval': ('string', 'remove_quotes,uppercase'),
             'file_type': ('string', 'remove_quotes'),
         }
         for climo_type in self.climo_types: