Tower cranes with concrete mass counterballance weights will 'weather cock' with the lifting boom into wind due to the wind resistance provided by the concrete. Those cranes that are catilever braced will tend to point downwind.
However IMHO they cannot be relied upon (apart from the flag as explained above) because there are so many variables that need to be satisfied. i.e Is there an operator in the cab, has the crane been left in freewheel mode, is the wind actually strong enough to weathercock it etc.
LM