User Configuration > Administrative Templates > Microsoft Outlook 2016 > Outlook Options > Preferences > Calendar Options
User
HKCU\software\policies\microsoft\office\16.0\outlook\options\calendar
This policy setting allows you to configure the weather service URL for Outlook. If you enable this policy setting, you must enter your desired weather service URL. If you disable or do not configure this policy setting, Outlook uses the default weather service URL.