You're right jings the Bewick swans do come every year, but one has arrived especially early this year.
This was the headline in the DT:
Britain faces longest winter in 50 years after earliest ever arrival of Siberian swan
The arrival of winter, traditionally heralded by the migration of Siberian swans, has come early as 300 birds flock to Britain
Then it goes on to say that just one has arrived!
DH reckons that if it is cold where they come from (Arctic Russia) they decide to come here earlier!
Temperatures are currently five to 10 degrees below average in parts of western Russia and eastern Europe and are expected to drop to the minus 30s
There's no reason why an icy blast should follow, as our weather predominantly comes from the west or south-west.
(although I have noticed more northerly and easterly winds in the last few years )