Reported via their Facebook page, this news also marks the closest transmission of a new episode of Doctor Who in the country to its UK transmission since the series returned in 2005.
In summary, transmission of The Snowmen is now confirmed for these dates:
United Kingdom : Tuesday 25th December, time tbc BBC One
United States : Tuesday 25th December, 9:00pm ET BBC America
Canada : Tuesday 25th December, 9:00pm ET SPACE
Australia : Wednesday 26th December, 7:30pm ABC1
New Zealand : Wednesday 26th December, time tbc Prime
(with thanks to Paul Scoones)