In this paper, a combination of data clustering and artificial intelligence techniques are used to predict incoming solar radiation on a daily basis. The data clustering technique known as Perceptually Important Points is proposed, where time-series data is grouped into clusters separated by key characteristic points, which are later used as training data for an artificial neural network. The type of network used is known as a Focused Time-Delay Neural Network, and an analysis of the data is performed using the Mean Absolute Percentage Error scheme.