What is the time difference from London to Rio?

London and Rio are located in different time zones. London is in the UTC+00:00 time zone, which means that its time is equal to the Coordinated Universal Time (UTC) offset by 00:00 hours. Rio de Janeiro is in the UTC-03:00 time zone, which means that its time is equal to UTC offset by -03:00 hours.

Therefore, the time difference between London and Rio de Janeiro is -03:00 hours.

Conclusion: When it is 12:00 PM in London, it would be 9:00 AM in Rio de Janeiro.