diff --git a/improver/wxcode/modal_code.py b/improver/wxcode/modal_code.py
index 799347eff3..2a8eb89aec 100644
--- a/improver/wxcode/modal_code.py
+++ b/improver/wxcode/modal_code.py
@@ -454,6 +454,8 @@ def _promote_time_coords(cube: Cube, template_cube: Cube) -> Cube:
 
         Args:
             cube: Cube with time coordinates.
+            template_cube: Cube to provide coordinates associated with the time
+                coordinate that will be added to the output cube.
 
         Returns:
             A cube with a time dimension coordinate and other time-related coordinates
@@ -565,6 +567,7 @@ def counts_per_category(data: np.ndarray, bin_max: int) -> np.ndarray:
         Args:
             data: Array where occurrences of each possible integer value between 0
                 and data.max() will be counted.
+            bin_max: Integer defining the number of categories expected.
 
         Returns:
             An array of counts for the occurrence of each category within each row.
@@ -702,7 +705,15 @@ def _get_most_likely_following_grouping(
     def _set_blended_times(cube: Cube, result: Cube) -> None:
         """Updates time coordinates so that time point is at the end of the time bounds,
         blend_time and forecast_reference_time (if present) are set to the end of the
-        bound period and bounds are removed, and forecast_period is updated to match."""
+        bound period and bounds are removed, and forecast_period is updated to match.
+        The result cube is modified in-place.
+
+        Args:
+            cube: Cube containing metadata on the temporal coordinates that will be
+                used to add the relevant metadata to the result cube.
+            result: Cube containing the computed modal weather code. This cube will be
+                updated in-place.
+        """
         result.coord("time").points = cube.coord("time").points[-1]
         result.coord("time").bounds = [
             cube.coord("time").bounds[0][0],
diff --git a/improver_tests/wxcode/wxcode/test_ModalFromGroupings.py b/improver_tests/wxcode/wxcode/test_ModalFromGroupings.py
index 52f30abfe2..18fddbe033 100644
--- a/improver_tests/wxcode/wxcode/test_ModalFromGroupings.py
+++ b/improver_tests/wxcode/wxcode/test_ModalFromGroupings.py
@@ -131,7 +131,9 @@
             ],
             [3, 4, 3, 7],
         ),
-        # Tied dry weather codes. The highest index weather code should be selected.
+        # Tied dry weather codes. The day version of the highest index weather code
+        # should be selected i.e. a partly cloudy night code (2) becomes a partly
+        # cloudy day code (3).
         ([0, 0, 0, 2, 2, 2, 7, 7], 3),
     ),
 )