This was my first time out in high winds we are on the extreme outer edge of the effects of hurricaine Matthew (mild stirring by comparison).  Winds are steady in the 10-15 MPH range and gusting at 20+.  The chime I used for reference is one of those heavy, low toned ones that the striker normally moves very slowly.  Hovering about 2 feet off the ground hands off the controls.
  

That's not really high winds, 10 to 15 mph is just a normal breeze. and 15 to 20 mph I would say just windy. Anything over 20 mph would be high winds for a Phantom. I personally go out in the 10 to 18 mph range all the time, and the Phantom handles it great. Just make sure you're flying into the wind, not with it. But once it hits 20+ things can get dicey.