diff --git a/toarstats/trends/utils.py b/toarstats/trends/utils.py
index aaa024610ec95a7dd2cbe983bdd823daea717343..0a07989d0c6fadc1115b6c3c4d0407ecbe982d2d 100644
--- a/toarstats/trends/utils.py
+++ b/toarstats/trends/utils.py
@@ -22,4 +22,8 @@ def deseasonalize(data):
         "+np.cos(month*4*np.pi/12)+np.sin(month*4*np.pi/12)",
         pd.DataFrame({"value": data["value"], "month": data.index.month})
     ).fit(method="qr").predict(pd.DataFrame({"month": range(1, 13)}))
-    return data
+    idx = data.index
+    return pd.DataFrame({
+        "value": data["value"].values - seasonal_cycle[idx.month-1].values,
+        "datetime": (idx.year-2000)*12 + idx.month
+    })