Hello, LJ57.
The wind sound signals an incoming projection. It is one of the sounds heard just before or a second after projecting; I also experience it often. Next time don't get preoccupied with sounds associated with a projection, just notice them and move on. Don't get distracted. You were very close, so keep trying and you'll make it!
Pan
This morning I woke up around 3AM and for the first time in ages I remembered to take advantage of the hypnagogic state and attempt projection. I was unable to project but I did get very close I believe. I started hearing the sound of wind like the sound of 40-50 mile per hour wind hitting a moving car. I have a small fan next to the bed but it doesn't sound anything like that. I thought maybe the sound was intensely amplified due to being in that state of mind. Has anyone experienced anything like this?