diff --git a/modules/aeolus/datasource.py b/modules/aeolus/datasource.py
index b47331ecc23733dfe767fe867eff1c9ab13158f4..ea4d41da3072526361b4c5f2d80dbee8f5729666 100644
--- a/modules/aeolus/datasource.py
+++ b/modules/aeolus/datasource.py
@@ -46,6 +46,8 @@ class Files:
     def get_file(self, timestamp, window=None):
         if window is None:
             window = self.span_seconds
+        else:
+            window = datetime.timedelta(minutes=window).seconds
         diff = self.ftimes[:, 0] - timestamp
         midx = np.argmin(np.abs(diff))
         if np.abs(self.ftimes[midx, 0] - timestamp) < window:
@@ -156,6 +158,8 @@ class AMVFiles:
     def get_file(self, timestamp, window=None):
         if window is None:
             window = self.span_seconds
+        else:
+            window = datetime.timedelta(minutes=window).seconds
         diff = self.ftimes[:, 0] - timestamp
         midx = np.argmin(np.abs(diff))
         if np.abs(self.ftimes[midx, 0] - timestamp) < window: