diff --git a/modules/util/util.py b/modules/util/util.py
index 2eecfd136ebd0bd1457fb3446afa933b327cb58d..65a2df0bcad339306023c03d3fa055b886b34f12 100644
--- a/modules/util/util.py
+++ b/modules/util/util.py
@@ -259,9 +259,11 @@ def get_grid_values_all(h5f, grid_name, scale_factor_name='scale_factor', add_of
 
 
 # dt_str_0: start datetime string in format YYYY-MM-DD_HH:MM
+# dt_str_1: stop datetime string, if not None num_steps is computed
 # num_steps with increment of days, hours, minutes or seconds
+# dt_str_1 and num_steps cannot both be None
 # return num_steps+1 lists of datetime strings and timestamps for the times eries
-def make_times(dt_str_0, num_steps, days=None, hours=None, minutes=None, seconds=None):
+def make_times(dt_str_0, dt_str_1=None, num_steps=None, days=None, hours=None, minutes=None, seconds=None):
     if days is not None:
         inc = 86400*days
     elif hours is not None:
@@ -275,6 +277,10 @@ def make_times(dt_str_0, num_steps, days=None, hours=None, minutes=None, seconds
     ts_s = []
     dto_0 = datetime.datetime.strptime(dt_str_0, '%Y-%m-%d_%H:%M').replace(tzinfo=timezone.utc)
     ts_0 = dto_0.timestamp()
+    if dt_str_1 is not None:
+        dto_1 = datetime.datetime.strptime(dt_str_1, '%Y-%m-%d_%H:%M').replace(tzinfo=timezone.utc)
+        ts_1 = dto_1.timestamp()
+        num_steps = int((ts_1 - ts_0)/inc)
 
     dt_obj_s.append(dto_0)
     ts_s.append(ts_0)