Traditionally, sea areas with a high mean wave power, ideally situated close to population centres, are seen as the most viable for harnessing economic wave energy. However, wave energy variability is a key driver of cost, since significant variation above the mean power will have implications for system rating and capacity and the capability to withstand high loads. Conversely, significant variation below the mean with result in ineffective power conversion, due to the robust nature of a wave energy converter with an ability to deal with high loads. Additional benefits of low power variability include smoother power production and increased value of generated electrical power. This paper demonstrated a prototype wave map which features wave power variability as a central figure of merit in the search for suitable wave energy sites. In particular, the coefficient of variability is introduced as a key metric. An on-line prototype map has been developed with a range of key information provided at a number of locations at which data was made available.