A key point to clarify is that when the wind speed is posted as 15 mph, you are probably only getting 5 mph or so at ground level. Buildings, trees, shrubs, and crops all beak up the wind. The 15 mph number is measured 30 feet above the ground with no obstructions for a significant distance. And remember, the wind speed at the ground is, by definition, zero. It is EXTREMELY unlikely that a rider would find themselves in an actual 15 mph wind. You can reverse engineer this by knowing how fast you can ride into a nominal 15 mph headwind. If you were actually experiencing that 15 mph, even a strong rider would unlikely be able to go even 10 mph, but you know that is not the case.