The other day, I had a claim repeated to me that says that wind turbines produce more power in rain. It's an appealing idea that I must imagine is based on rain being denser than air. There is a change in momentum when air hits the wind turbine. For the same change of speed, water would produce a bigger change in momentum and thus more force. If this is true, I can find no reference to it online. This paper only deals with Vertical Axis turbines whereas the common ones pictured are horizontal axis. It suggests that VAWTs perform worse in the rain.
