Yes, to a degree. A 2008 study showed that large wind farms actually have an impact on local weather and climate. When one thinks about it, this makes sense. Farmers have for years been using large fans to decrease humidity and warm crops when there is a risk of a freeze. Wind farms, too, cause a decrease in humidity and raise temperatures, especially during the morning hours. The question becomes, as we construct more and more wind farms, how many windmills will it take to make a worldwide impact on weather and climate?