Outlook 15 allows you to display the weather in the calendar for various locations.
Unfortunately, even though adding cities to the list there is trivial, deleting the locations is not.

The question was raised in the Answers forums. I asked around and here’s the information I collected:

The list of locations shows the last 5 used locations and cannot be removed manually.
The Outlook preferences file has these locations, and removing the preferences would therefore clear the locations. However removing the preferences file would also reset other settings obviously!

The file is here: ~/Library/Containers/com.microsoft.Outlook/Data/Library/Preferences/com.microsoft.outlook.plist but simply trashing it would prevent it from being properly recreated and you will be continually prompted by the add account wizard every time you launch Outlook.

You should quit Outlook and use the defaults delete com.microsoft.Outlook terminal command to remove preferences. It will delete ALL Outlook preferences (preferences though, not account settings, rules, etc).

In order to re-enable the automatically update location option, you need to go to Location Services in System Preferences and grant access to location data to Outlook.