Worldwide wind speeds have slowed down by about half a kilometer per hour (0.3 miles per hour) since the 1960s according to researchers. 31
The phenomenon is known as 'stilling', and scientists are not sure why it is happening. They speculate that it may have something to do with urbanization, climate change and cumulus clouds. But then researchers admit: “Or it could be due to aging wind speed instruments producing inaccurate results.”