A method for operating an irrigation control system is provided and includes receiving environmental data by the irrigation control system and receiving operational data from an array of photovoltaic cells. The method further includes determining an amount of cloud cover in the sky from the array of photovoltaic cells and calculating an evapotranspiration value for an irrigation zone associated with the irrigation control system based at least in part upon the environmental data and the operational data. The method still further includes determining an irrigation schedule for the irrigation zone based at least in part upon the evapotranspiration value and executing the irrigation schedule to irrigate the irrigation zone. An irrigation control system is also provided.
