diff --git a/climax/main/preprocess_ERA5.py b/climax/main/preprocess_ERA5.py
index c12efba53a9d139b0d57586c9ae653797b1cdd8c..44961d19f3e56726d74a729920af366aca9931be 100644
--- a/climax/main/preprocess_ERA5.py
+++ b/climax/main/preprocess_ERA5.py
@@ -89,7 +89,7 @@ if __name__ == '__main__':
             # days
             LOGGER.info('Computing daily averages ...')
             for src, tmp in zip(source, dlyavg):
-                ds = xr.open_dataset(source)
+                ds = xr.open_dataset(src)
 
                 # compute daily averages
                 ds = ds.resample(time='D').mean(dim='time')