diff --git a/pyleoclim/core/ensembleseries.py b/pyleoclim/core/ensembleseries.py
index 42ef22d3..c84fc871 100644
--- a/pyleoclim/core/ensembleseries.py
+++ b/pyleoclim/core/ensembleseries.py
@@ -469,7 +469,10 @@ def quantiles(self, qs=[0.05, 0.5, 0.95], axis = 'value'):
             vals = []
             for ts in self.series_list:
                 if not np.array_equal(ts.time, time):
-                    raise ValueError('Time axis not consistent across the ensemble!')
+                    raise ValueError(
+                        'Time axis not consistent across the ensemble! '
+                        'Apply common_time() first to place all members on a shared time axis.'
+                    )
     
                 vals.append(ts.value)
     
diff --git a/pyleoclim/tests/test_core_EnsembleSeries.py b/pyleoclim/tests/test_core_EnsembleSeries.py
index 56b9686f..4eca73a1 100644
--- a/pyleoclim/tests/test_core_EnsembleSeries.py
+++ b/pyleoclim/tests/test_core_EnsembleSeries.py
@@ -286,6 +286,18 @@ def test_quantiles_t0(self):
 
         ens_qs = ts_ens.quantiles()
 
+    def test_quantiles_mismatched_time_axes(self):
+        """axis='value' requires a shared time axis; the error must name the fix"""
+        nt = 50
+        t, v = pyleo.utils.gen_ts(model="colored_noise", nt=nt, alpha=1.0)
+        base = pyleo.Series(t, v, verbose=False)
+        shifted = pyleo.Series(t + 1, v, verbose=False)
+
+        ts_ens = pyleo.EnsembleSeries([base, shifted])
+
+        with pytest.raises(ValueError, match="common_time"):
+            ts_ens.quantiles(axis="value")
+
     def test_quantiles_t1(self):
 
         nn = 30  # number of age models