diff --git a/msgpack/ext.py b/msgpack/ext.py
index 9694819a..37a1c580 100644
--- a/msgpack/ext.py
+++ b/msgpack/ext.py
@@ -157,9 +157,10 @@ def to_datetime(self):
         :rtype: `datetime.datetime`
         """
         utc = datetime.timezone.utc
-        return datetime.datetime.fromtimestamp(0, utc) + datetime.timedelta(
+        utcDatetime = datetime.datetime.fromtimestamp(0, utc) + datetime.timedelta(
             seconds=self.seconds, microseconds=self.nanoseconds // 1000
         )
+        return utcDatetime.astimezone(tz=None)
 
     @staticmethod
     def from_datetime(dt):
diff --git a/msgpack/unpack.h b/msgpack/unpack.h
index 58a2f4f5..c409c1b0 100644
--- a/msgpack/unpack.h
+++ b/msgpack/unpack.h
@@ -355,10 +355,12 @@ static int unpack_callback_ext(unpack_user* u, const char* base, const char* pos
                 return -1;
             }
 
-            py = PyNumber_Add(epoch, d);
+            PyObject *added = PyNumber_Add(epoch, d);
+            py = PyObject_CallMethod(added, "astimezone", "O", Py_None);
 
             Py_DECREF(epoch);
             Py_DECREF(d);
+            Py_DECREF(added);
         }
         else { // float
             PyObject *a = PyFloat_FromDouble((double)ts.tv_nsec);