diff --git a/mlair/plotting/postprocessing_plotting.py b/mlair/plotting/postprocessing_plotting.py
index 1a19c50c8337b4c1edf00d9f19debd2cdba07a22..6f073682eec76bff216c4e4f4dbdd3918f2d8d80 100644
--- a/mlair/plotting/postprocessing_plotting.py
+++ b/mlair/plotting/postprocessing_plotting.py
@@ -1303,6 +1303,7 @@ class PlotTimeEvolutionMetric(AbstractPlotClass):
 
     def _plot(self, data, years, months, vmin=None, vmax=None, subtitle=None):
         fig, ax = plt.subplots(figsize=(max(data.shape[1] / 5, 12), max(data.shape[0] / 2.8, 2)))
+        data.sort_index(inplace=True)
         sns.heatmap(data, linewidths=1, cmap="coolwarm", ax=ax, vmin=vmin, vmax=vmax,
                     cbar_kws={"aspect": self._aspect_cbar(data.shape[0])})
         # or cmap="Spectral_r", cmap="RdYlBu_r", cmap="coolwarm",