GH ref for 30460

pandas-dev · simonjayhawkins · Dec 31, 2019 · Dec 26, 2019 · Dec 26, 2019 · Dec 27, 2019
commit 8ba1bfdf80cd59c7a851a002c883836ec4f240f1
diff --git a/doc/source/whatsnew/v1.0.0.rst b/doc/source/whatsnew/v1.0.0.rst
@@ -716,6 +716,7 @@ Datetimelike
 - Bug in :meth:`Series.item` with ``datetime64`` or ``timedelta64`` dtype, :meth:`DatetimeIndex.item`, and :meth:`TimedeltaIndex.item` returning an integer instead of a :class:`Timestamp` or :class:`Timedelta` (:issue:`30175`)
 - Bug in :class:`DatetimeIndex` addition when adding a non-optimized :class:`DateOffset` incorrectly dropping timezone information (:issue:`30336`)
 - Bug in :meth:`DataFrame.append` would remove the timezone-awareness of new data (:issue:`30238`)
+- Bug in :meth:`Series.cummin` and :meth:`Series.cummax` with timezone-aware dtype incorrectly dropping its timezone (:issue:`15553`)
 
 Timedelta
 ^^^^^^^^^

diff --git a/pandas/core/generic.py b/pandas/core/generic.py
@@ -11106,6 +11106,7 @@ def cum_func(self, axis=None, skipna=True, *args, **kwargs):
         d["copy"] = False
 
         if issubclass(y.dtype.type, (np.datetime64, np.timedelta64)):
+            # GH#30460, GH#29058
             # numpy 1.18 started sorting NaTs at the end instead of beginning,
             #  so we need to work around to maintain backwards-consistency.
             orig_dtype = y.dtype