in Configurations under application settings
you can use WEBSITE_TIME_ZONE and value
Pacific Standard Time or America/Los_Angeles or US/pacific, based your US/los angeles.
you can check via webssh,
you can check in the page for more details.
https://learn.microsoft.com/en-us/azure/app-service/reference-app-settings?tabs=kudu%2Cdotnet#app-environment
and the values https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-vista/cc749073(v=ws.10)