diff --git a/notebooks/wp4/clima_and_bias_cordex_cmip6_regionalised.ipynb b/notebooks/wp4/clima_and_bias_cordex_cmip6_regionalised.ipynb
index 48ee64e..d663918 100644
--- a/notebooks/wp4/clima_and_bias_cordex_cmip6_regionalised.ipynb
+++ b/notebooks/wp4/clima_and_bias_cordex_cmip6_regionalised.ipynb
@@ -269,7 +269,11 @@
     "    else:\n",
     "        # Select years (shift -1 to get D(year-1)J(year)F(year))\n",
     "        ds = ds.assign_coords(year=ds[\"time\"].dt.year.shift(time=-1))\n",
-    "        mask = (ds[\"year\"] >= year_start) & (ds[\"year\"] <= year_stop)\n",
+    "        mask = (\n",
+    "            (ds[\"year\"] >= year_start)\n",
+    "            & (ds[\"year\"] <= year_stop)\n",
+    "            & (ds[\"time\"].dt.season == timeseries)\n",
+    "        )\n",
     "    ds = ds.where(mask.compute(), drop=True)\n",
     "    if not ds.sizes[\"time\"]:\n",
     "        # Return empty dataset. Previous year needed for DJF only.\n",