Merge pull request #234052 from KrishnaG-MSFT/patch-284

(AzureCXP) MicrosoftDocs/azure-docs#107730

Author: prmerger-automator[bot]

articles/azure-monitor/essentials/metrics-store-custom-rest-api.md

@@ -114,7 +114,7 @@ Save the access token from the response for use in the following HTTP requests.
     -d @custommetric.json 
     ```
 
-1. Change the timestamp and values in the JSON file.
+1. Change the timestamp and values in the JSON file. Note that the 'time' value in the JSON file is expected to be in UTC.
 1. Repeat the previous two steps a few times to create data for several minutes.
 
 ## Troubleshooting