Climate extremes have profound implications for urban infrastructure and human society, but studies of observed changes in climate extremes over the global urban areas are few, even though more than half of the global population now resides in urban areas. Here, using observed station data for 217 urban areas across the globe, we show that these urban areas have experienced significant increases (p-value <0.05) in the number of heat waves during the period 1973–2012, while the frequency of cold waves has declined.

India is rapidly developing wind energy resources to satisfy its growing needs for electricity. However, the suitability of a particular location for the development of a wind energy project depends on a large number of factors.