This is held until the 50 feet, then it can be bled off, but under really gusty conditions, you will probably touch down above Vref
The 737 FCTM states all the gust and half the steady headwind component with the proviso that the latter is bled off approaching touchdown. This means you have to deliberately start to bleed off the steady HW component well before 50 feet - more like 300 feet as you will only lose three knots in the flare. Many over-run accidents are caused by pilots electing not to bleed off the 1/2 HW and thus coming over the fence with excess speed and floating.