The transformation of the electricity market structure from a monopoly model to a competitive market has caused electricity to be exchanged like a commercial commodity in the electricity market. The electricity price participants should forecast the price in different horizons to make an optimal offer as a buyer or a seller. Therefore, accurate electricity prices prediction is very important for market participants. In this paper, the impact of monthly/seasonal data clustering impact on price forecasting investigates. After clustering the data, the effective parameters in the electricity price forecasting problem are selected using grey correlation analysis method and the parameters with low degree of correlation are removed. At the end, the long short-term memory neural network has been implemented to predict the electricity price for the next day. The proposed method is implemented on Ontario-Canada data and the prediction results are compared in three modes including non-clustering, seasonal and monthly clustering. The studies show that the prediction error in the monthly clustering mode has decreased compared to the non-clustering and seasonal clustering modes in two different values of the correlation coeffi-cient 0.5 and 0.6.
