Using the orientation sensors of the Phantom 2, it should be possible to estimate wind speed. If the maximum wind speed is exceeded the Vision App should be able to warn users of high winds. This is particularily important for high altitude flights due to winds aloft. It may be fairly calm on the ground but there could be a 40mph wind a few hundred feet above.
There are several ways to estimate wind speed. One way is to look at the tilt of the drone when it is holding position. Another way is to compare the expected tilt and speed to the actual tilt and speed for directional travel. This would only be a rough estimate that could be displayed as 0-20, 20-40 and 40+ mph speeds (assuming English units). It would also be helpful to know if the wind is constant or gusty.

Well, if the max speed of the Phantom is published at 33.5 mph, any wind above that would blow your Phantom away even if you were locked in with GPS.  The Phantom would be working to the max speed to keep position, but unable to do so. so it would be drifting at 6.5 miles an hour with the wind.  It would not keep up.
As far as having an estimated wind speed indicator,  they already have that.  Just look at your distance gauge from home point, if it is stable at say 45 feet and not changing, and your air speed indicator at 100 feet up is 5 mph,  the wind speed at 100 feet is 5 mph.

I will take a look at the air speed indicator. Are you sure that this is a true air speed measurement and not just the motion of the drone using GPS coordinates?

grangerfx.gmail Posted at 2015-2-3 14:22
I will take a look at the air speed indicator. Are you sure that this is a true air speed measuremen ...

The drone was not drifting at all, it stayed at 150 feet above me. My position (distance from home) stayed at 6 feet from me in 1 position with 9 sat locks, did not move at all and the speed indicated 6.5 mph.  It was reading 0 on the ground.