diff --git a/city_metrix/layers/era_5_hottest_day.py b/city_metrix/layers/era_5_hottest_day.py
index 44718eb..019f6a0 100644
--- a/city_metrix/layers/era_5_hottest_day.py
+++ b/city_metrix/layers/era_5_hottest_day.py
@@ -136,8 +136,8 @@ def hourly_mean_temperature(image):
             for file in glob.glob(f'download_{i}.grib*'):
                 os.remove(file)
 
-        an_data = xr.concat(an_list, dim='time')
-        fc_data = xr.concat(fc_list, dim='time')
+        an_data = xr.concat(an_list, dim='time').dropna(dim='time')
+        fc_data = xr.concat(fc_list, dim='time').dropna(dim='time')
         fc_data = fc_data.sel(time=~fc_data.indexes['time'].duplicated())
         fc_data = fc_data.transpose(*an_data.dims)
 
diff --git a/tests/test_metrics.py b/tests/test_metrics.py
index 5c6e85f..d8634db 100644
--- a/tests/test_metrics.py
+++ b/tests/test_metrics.py
@@ -27,6 +27,8 @@ def test_built_land_without_tree_cover():
 @pytest.mark.skipif(EXECUTE_IGNORED_TESTS == False, reason="CDS API needs personal access token file to run")
 def test_era_5_met_preprocess_portland():
     indicator = era_5_met_preprocessing(OR_PORTLAND_NO_TILE_ZONE)
+    has_nan_values = indicator.direct_rad.isna().any()
+    assert has_nan_values == False
     assert len(indicator) == 24