The UK is divided into wind zones by the fundamental basic wind velocity (Vb,0) map in the NA to EN 1991-1-4. Sites in western Scotland, northern and western coasts, and exposed upland areas have higher fundamental basic wind velocities than sheltered central and eastern lowland areas. The site-specific design wind speed also depends on altitude, terrain category, and building height.
For rooftop solar PV, the wind zone has a direct effect on calculated uplift forces on panels and the required ballast weight or fixing capacity. A site in a high wind zone may require significantly more ballast per panel than the same system in a low wind zone, which in turn requires a stronger roof structure to carry the combined loads.