Expectations of wind energy are high, but large offshore wind projects are also quite expensive. To get insight into these costs, computer models are used that mimic offshore wind farms, much like a computer game. For example, the 'players' can build a wind farm and move wind turbines around at will. They can see how this affects the total energy that is produced, and find the best layout. However, the scenario's in these 'games' are only useful if the simulated wind is realistic. That's what this thesis is about: getting realistic wind into wind farm simulations. We compared measurements of the real offshore wind with simulations in the 'virtual' wind farm. An important finding is that in order to get the wind right, temperature is also important. The sea is much colder in spring than in autumn, and this affects the wind. Wind farm models will give better results if this is taken into account.