BUG: pandas Timestamp tz_localize and tz_convert do not preserve freq attribute

pandas/_libs/tslibs/timestamps.pyx

@@ -1187,12 +1187,12 @@ class Timestamp(_Timestamp):
             value = tz_localize_to_utc(np.array([self.value], dtype='i8'), tz,
                                        ambiguous=ambiguous,
                                        nonexistent=nonexistent)[0]
-            return Timestamp(value, tz=tz)
+            return Timestamp(value, tz=tz, freq=self.freq)
         else:
             if tz is None:
                 # reset tz
                 value = tz_convert_single(self.value, UTC, self.tz)
-                return Timestamp(value, tz=None)
+                return Timestamp(value, tz=None, freq=self.freq)
             else:
                 raise TypeError('Cannot localize tz-aware Timestamp, use '
                                 'tz_convert for conversions')
@@ -1222,7 +1222,7 @@ class Timestamp(_Timestamp):
                             'tz_localize to localize')
         else:
             # Same UTC timestamp, different time zone
-            return Timestamp(self.value, tz=tz)
+            return Timestamp(self.value, tz=tz, freq=self.freq)
 
     astimezone = tz_convert
 

pandas/tests/tslibs/test_conversion.py

@@ -66,3 +66,12 @@ def test_length_zero_copy(dtype, copy):
     arr = np.array([], dtype=dtype)
     result = conversion.ensure_datetime64ns(arr, copy=copy)
     assert result.base is (None if copy else arr)
+
+
+def test_tz_convert_freq():
+    import pandas as pd
+    import pytz
+    t1 = pd.Timestamp('2019-01-01 10:00', freq='H')
+    assert t1.tz_localize(pytz.utc).freq == t1.freq
+    t2 = pd.Timestamp('2019-01-02 12:00', tz=pytz.utc, freq='T')
+    assert t2.tz_convert(pytz.utc).freq == t2.freq