diff --git a/pandas/core/indexes/datetimes.py b/pandas/core/indexes/datetimes.py
index fa4463295e3357..fc887fce47815d 100644
--- a/pandas/core/indexes/datetimes.py
+++ b/pandas/core/indexes/datetimes.py
@@ -2026,6 +2026,11 @@ def month_name(self, time_locale=None):
         month_names : Index
             Index of month names
         """
+        values = self.asi8
+        if self.tz is not None:
+            if self.tz is not utc:
+                values = self._local_timestamps()
+
         result = fields.get_date_name_field(values, 'month_name',
                                             time_locale=time_locale)
         result = self._maybe_mask_results(result)
@@ -2045,6 +2050,11 @@ def day_name(self, time_locale=None):
         month_names : Index
             Index of day names
         """
+        values = self.asi8
+        if self.tz is not None:
+            if self.tz is not utc:
+                values = self._local_timestamps()
+
         result = fields.get_date_name_field(values, 'day_name',
                                             time_locale=time_locale)
         result = self._maybe_mask_results(result)
diff --git a/pandas/tests/indexes/datetimes/test_misc.py b/pandas/tests/indexes/datetimes/test_misc.py
index 15b2b6ddd80f58..9fd028af5ba39b 100644
--- a/pandas/tests/indexes/datetimes/test_misc.py
+++ b/pandas/tests/indexes/datetimes/test_misc.py
@@ -356,7 +356,7 @@ def test_datetime_name_accessors(self, time_locale):
             tm.assert_index_equal(result, expected)
             for date, expected in zip(dti, calendar.month_name[1:]):
                 result = date.month_name(time_locale=time_locale)
-                assert result == expected.capitalize() 
+                assert result == expected.capitalize()
 
     def test_nanosecond_field(self):
         dti = DatetimeIndex(np.arange(10))
diff --git a/pandas/tests/scalar/test_timestamp.py b/pandas/tests/scalar/test_timestamp.py
index 9722dcbf4c036d..cffcd51fee98cc 100644
--- a/pandas/tests/scalar/test_timestamp.py
+++ b/pandas/tests/scalar/test_timestamp.py
@@ -612,7 +612,7 @@ def test_day_name(self, data, time_locale):
         with tm.set_locale(time_locale, locale.LC_TIME):
             expected = calendar.day_name[0].capitalize()
             result = data.day_name(time_locale)
-            assert result == expected 
+            assert result == expected
 
     def test_pprint(self):
         # GH12622