Pre-requisites (USER ACTION REQUIRE):
1) Stream_Weather_2_<GUID>.dat file must be available at: %userprofile%\AppData\Local\Microsoft\Outlook\RoamCache
1.1) Create it manually by, Clicking on a little drop-down button in the Weather Bar and Add another city. Then change it back to the one you want.
Set Temperature Unit via GPO using PolicyPak Scripts Manager:
You will be able to set Celsius as default temperature (as shown in following screenshot), instead of Fahrenheit.
Temperature unit information appears to be controlled via Stream_Weather_2_<unique-guid>.dat file at this location: %userprofile%\AppData\Local\Microsoft\Outlook\RoamCache
We can change the DegreeType to 9-1 to convert it to Celsius. But as filename has a unique GUID for each user so please follow these steps to apply the change via PowerShell Script using PolicyPak Scripts Manager.
Right-click and Add Policy for PolicyPak Scripts Manager under User Configuration
Click Next on the Wizard and Select PowerShell script from the drop-down. Insert the following script. Then select both checkboxes, Run script as user and With elevated rights.
$Path = "$env:USERPROFILE\AppData\Local\Microsoft\Outlook\RoamCache\*"
$FileName = (Get-Item -Path $Path -Filter "Stream_Weather*.dat").FullName
$Content = Get-Content -path $FileName
Stop-Process -Name outlook -Force -ErrorAction SilentlyContinue
Set-Content $FileName $content.Replace("DegreeType"" v=""9-1""", "DegreeType"" v=""9-0""")
TIP: Outlook has to be closed to make this change, so be sure to add the "stop-process" line before the "set-content".
Finally, select an option to apply Once or when forced, and complete the remaining steps on the wizard.