Hi Andrew,
Wind chill factor? sounds too cold for some of us.
You guys are so lucky with the SW wind at Sandy Point, few here in Auckland are planning on flying to Sandy Point regularly when conditions are Primo

(more imports).
Lots of snow in NZ already, could be the year to visit our NZ slopes.
This year I'm taking the kids to the snow at Mt Ruapehu, just need to wait for a High Pressure system to be over the North Island during winter, there is no fun being up the mountain with a strong SW wind ~ wind chill -30C is too cold while sitting on a chair lift!