diff --git a/tests/test_indices.py b/tests/test_indices.py
index 28f5032a5..3fcd31319 100644
--- a/tests/test_indices.py
+++ b/tests/test_indices.py
@@ -494,12 +494,12 @@ def test_effective_growing_degree_days(
 class TestStandardizedIndices:
     # gamma/APP reference results: Obtained with `monocongo/climate_indices` library
     # MS/fisk/ML reference results: Obtained with R package `SPEI`
-    # Using the method `APP` in XClim matches the method from monocongo, hence the very low
-    # tolerance possible.
+    # Using the method `APP` in XClim matches the method from monocongo, hence the very low tolerance possible.
     # Repeated tests with lower tolerance means we want a more precise comparison, so we compare
-    # the current version of XClim with the version where the test was implemented
+    # the current version of XClim with the version where the test was implemented.
+    # Additionally, xarray does not yet access "week" or "weekofyear" with groupby in a pandas-compatible way for cftime objects.
+    # See: https://github.com/pydata/xarray/discussions/6375
     @pytest.mark.slow
-    @pytest.mark.filterwarnings("ignore:dt.weekofyear and dt.week have been deprecated")
     @pytest.mark.parametrize(
         "freq, window, dist, method,  values, diff_tol",
         [