diff --git a/esmvaltool/diag_scripts/monitor/multi_datasets.py b/esmvaltool/diag_scripts/monitor/multi_datasets.py
index 44ed36a086..8a15b6cc4a 100644
--- a/esmvaltool/diag_scripts/monitor/multi_datasets.py
+++ b/esmvaltool/diag_scripts/monitor/multi_datasets.py
@@ -670,12 +670,6 @@ def _load_and_preprocess_data(self):
                 z_coord = cube.coord('altitude')
                 z_coord.attributes['positive'] = 'up'
 
-            # Convert pr units if necessary
-            if cube.var_name == 'pr' and cube.units == 'kg m-2 s-1':
-                cube.units = 'mm s-1'
-                cube.convert_units('mm day-1')
-                dataset['units'] = 'mm day-1'
-
             dataset['cube'] = cube
 
         return input_data