diff --git a/weather_api.py b/weather_api.py
index 5ea2700..a189cc7 100644
--- a/weather_api.py
+++ b/weather_api.py
@@ -26,12 +26,12 @@ def period_to_start_end(period):
     end = period.split('|')[1]
     return start, end
 
-def get_num_days(start, end):
-    """ returns the number of days between the start and end date """
-    start_date = datetime.strptime(start, '%Y-%m-%d')
-    end_date = datetime.strptime(end, '%Y-%m-%d')
-    delta = end_date - start_date
-    return delta.days
+def get_num_days(start, end):
+    """ returns the number of days between the start and end date """
+    start_date = datetime.strptime(start, '%Y-%m-%d')
+    end_date = datetime.strptime(end, '%Y-%m-%d')
+    delta = end_date - start_date
+    return delta.days + 1
 
 
 def get_num_obs(start, end, aggregator):