diff --git a/scripts/resample_daily.py b/scripts/resample_daily.py
index 1172b07..e3cbc77 100644
--- a/scripts/resample_daily.py
+++ b/scripts/resample_daily.py
@@ -170,7 +170,7 @@ def main(argv: abc.Sequence[str]) -> None:
           orig_times.min() - np.timedelta64(rolling_window - 1, 'D'),
           orig_times.max() - np.timedelta64(rolling_window - 2, 'D'),
           dtype='datetime64[D]',
-      )
+      ).astype('datetime64[ns]')
   elif METHOD.value == 'resample':
     if PERIOD.value[-1] == 'w':
       raise NotImplementedError(
@@ -181,7 +181,7 @@ def main(argv: abc.Sequence[str]) -> None:
           orig_times.min(),
           orig_times.max() + np.timedelta64(1, 'D'),
           dtype='datetime64[D]',
-      )
+      ).astype('datetime64[ns]')
   else:
     raise ValueError(f'Method {METHOD.value} not supported.')
 
diff --git a/weatherbench2/utils.py b/weatherbench2/utils.py
index 2cc327a..dd02e6c 100644
--- a/weatherbench2/utils.py
+++ b/weatherbench2/utils.py
@@ -39,7 +39,7 @@ def select_hour(ds: xr.Dataset, hour: int) -> xr.Dataset:
   # Select hour
   ds = ds.isel(time=ds.time.dt.hour == hour)
   # Adjust time dimension
-  ds = ds.assign_coords({'time': ds.time.astype('datetime64[D]')})
+  ds = ds.assign_coords({'time': ds.time.astype('datetime64[ns]')})
   return ds