Surface winds fluctuate. From around 1980 to 2010, surface onshore winds generally became weaker, and they have gained in strength since then. While these fluctuations are well known, we currently do not fully understand why they happen. To investigate the reasons, we use a large set of climate simulations with one model, a so-called large ensemble. We find that the observed long-term wind fluctuations occur naturally under current and future conditions and do not require a specific trigger.