add tests for dst transition plotting

Author: Faheem12005

pandas/plotting/_matplotlib/timeseries.py

@@ -251,13 +251,13 @@ def use_dynamic_x(ax: Axes, index: Index) -> bool:
             return index[:1].is_normalized
         period = Period(index[0], freq_str)
         assert isinstance(period, Period)
+        period_naive = period.to_timestamp()
         if index.tz is not None:
             # Compare naive local times directly
-            period_naive = period.to_timestamp()
-            index_naive = index[0].tz_localize(None)  # Strips tz, keeps local time
-            return period_naive == index_naive
+            tz_naive = index[0].tz_localize(None)  # Strips tz, keeps local time
+            return period_naive == tz_naive
         else:
-            return period.to_timestamp() == index[0]
+            return period_naive == index[0]
 
     return True
 

pandas/tests/plotting/test_series.py

@@ -1003,3 +1003,19 @@ def test_bar_line_plot(self):
         x_limits = ax.get_xlim()
         assert x_limits[0] <= bar_xticks[0].get_position()[0]
         assert x_limits[1] >= bar_xticks[-1].get_position()[0]
+
+    def test_tseries_plot_dst_transition(self):
+        """
+        Test that plotting tz-aware timeseries works during DST fall-back transition.
+        #62936
+        """
+        tind = pd.date_range(
+            "2025-10-26T00:00:00Z",
+            "2025-10-26T03:00:00Z",
+            freq="5min",
+            tz="utc",
+        ).tz_convert("MET")[12:]
+        
+        myts = DataFrame({"a": 1}, index=tind)
+        _check_plot_works(myts.plot)
+