thestig said...
Does anyone actually know why the North Head wind meter always ends up blowing around 5-7 knots lower than botany bay does
Because it gets 5-7 knots less wind

For some reason Botany gets better seabreezes. I don't claim to understand why, but it has always been the case.
On the other hand the Northern Beaches do have much better spots for southerlies and big swell / surf