diff --git a/src/anemoi/graphs/nodes/attributes.py b/src/anemoi/graphs/nodes/attributes.py
index db4ffa1..c88ea7f 100644
--- a/src/anemoi/graphs/nodes/attributes.py
+++ b/src/anemoi/graphs/nodes/attributes.py
@@ -155,7 +155,14 @@ def get_raw_values(self, nodes: NodeStorage, **kwargs) -> np.ndarray:
         sv.regions = [region for region in sv.regions if region]
         # compute the area weight without empty regions
         area_weights = sv.calculate_areas()
-        # add them back with zero weight
+        if (null_nodes := mask.sum()) > 0:
+            LOGGER.warning(
+                "%s is filling %d (%.2f%%) nodes with value %f",
+                self.__class__.__name__,
+                null_nodes,
+                100 * null_nodes / len(mask),
+                self.fill_value,
+            )
         result = np.ones(points.shape[0]) * self.fill_value
         result[mask] = area_weights
         LOGGER.debug(