There is an increased risk the higher the wind speed, but it's easy to oversimplify the issue:
- GUSTS. The average wind speed may be reported as 10 MPH, for example, but there may be gusts much higher than that. Some days you just have a constant wind speed without much fluctuation, while other days you may have gusts that blow much higher than the average. The risks here are obvious, such as a gust blowing your bird into an obstacle.
- ALTITUDE. Wind speed can vary depending on altitude as well. The wind speed is typically faster the higher you go, and you could easily get into trouble if you aren't prepared for it. Again, this can vary widely depending on the day, location, and weather pattern.
- GPS, ATTI and RTH. If you are in P mode with a good GPS signal, the bird will most likely be able to remain fairly steady even in moderate winds (as others have attested to). And as long as everything is stable with your GPS signal, you'll most likely be fine. However, if it loses GPS signal and goes into ATTI mode, you could get into big trouble if you aren't quick to react and are able to adjust your orientation. And in ATTI mode, the wind could easily blow your bird into an obstacle if you aren't careful. On the other hand, if your bird goes into RTH mode and isn't making progress coming home (RTH uses lower power than normal), then you may have to cancel RTH and fly manually.
- DIRECTION. If you fly with the wind to a pretty far distance and get low battery, you may not have enough battery to get back home even though the bird thought you would. In most cases, you'll likely be fine, but there's a chance that it could just land somewhere else if it gets to critical battery before returning home.
So it's not like you can't fly in the wind, but be smart and take extra precaution:
- Stay further away from obstacles
- Keep an extra eye on battery level
- Be aware of both wind speed and wind direction
- Be aware wind changes as you climb higher
- Be prepared to fly manually