Wind Power is the perfect addition to your off grid solar set-up.  As usual if there is no sun, there is wind, so it enables you to keep your power going during darker winter times.

However, please note that a wind turbine's wind speed rating is calculated in stable, non-turbulent, wind. Wind turbines should be mounted at least 6 -10m above ground level and as far away from any obstructions that can cause turbulence as is feasible, so away from trees, buildings and roofs. Below this height the boundary layer between the ground and the body of air moving over it is so turbulent that wind turbines will not function well, if at all. At best they will function to deliver power at the lowest turbulent air speed,so if you wind gusting between 4 and 20m's you will get an output of around 4m/s.