[Parmy]

What you say is undoubtedly true, but there is a warm inversion above the cold air at the surface, even in the winter. And what the fans do is cause the minicus(sp) layer to be penetrated so the warmer air can be mixed with the colder air to raise the surface temperature above the critical point that would damage the fruit buds.

We have done this for years, and it works. There are other factors in play here as well. For instance, the effectiveness of the fans ability to raise the temperature depends upon the dew point. The higher the dew point, the more the temperature can be raised, conversely, the lower the dew point, the less effective the fans are in raising the temperature.

[BillM]

This attempts to explain the dew point thing.