diff --git a/usage_function/README.md b/usage_function/README.md
index 9331820..d84b8c8 100644
--- a/usage_function/README.md
+++ b/usage_function/README.md
@@ -5,6 +5,6 @@ It will get all the usage data for subscriptions in a management group or billin
 
 `costmanagement` is also an Azure function. It should be deployed to the same function app as the `usage` function.
 
-`monthly_usage` uses similar code as `usage` but runs on the 7th day of each month to get the previous month's usage.
+`monthly_usage` uses similar code as `usage` but runs bi-hourly on the 7th and 8th day of each month to get the previous month's usage.
 
 See the docs for more.
diff --git a/usage_function/monthly_usage/__init__.py b/usage_function/monthly_usage/__init__.py
index 5df8b0e..166e449 100644
--- a/usage_function/monthly_usage/__init__.py
+++ b/usage_function/monthly_usage/__init__.py
@@ -93,9 +93,9 @@ def main(mytimer: func.TimerRequest) -> None:
         try:
             usage_items = retrieve_usage(usage_query)
 
-            isodate = datetime.now().isoformat()
+            today = date.today()
             for usage_item in usage_items:
-                usage_item.monthly_upload = isodate
+                usage_item.monthly_upload = today
 
             logger.warning("Sending usage for %s", dates)
             send_usage(config.API_URL, usage_items, monthly_usage_upload=True)