I think it's that windy its blown the weather vain right around ?

Strewth! sounds like a reasonable explanation

I'd say it's had something blow loose that keeps it pointing in the right direction.

Looks like it's just the reverse of what's actually going on...

this was the reason

from fremantle sea rescue facebook page

ANNOUNCEMENT:
The Bureau of Meteorology wind reading equipment at Rottnest Island, Western Australia has been damaged by wind and is currently reading opposite to the actual wind direction.