I the UK the heavy winds and the rain comes mainly from the southwest so point it it south east or east, to keep the rain from blowing into your loft.
Also the cold winter winds come from the north east, and snow generally comes from the north west,
This has also been backed up by observing the birds in our dove cotes,
In this one the only ones that are ocupied over the winter are the ones pointing south east. The last ones to be picked in the summer are the southwest ones
This one is never occupied as I think it is on on a south facing wall, notice how clean it is becase it is never used
This one is always occupied and they raise good strong healthy young all year round in it, the wall is facing east.
Our lofts face east
Maybe the birds know more that us ;D ;D ;D