Long time series of daily meteorological data that are needed in various applications are not always available or appropriate for use at many locations. The temperature simulation model generated using three years data (2000, 2001 and 2002) was evaluated.Its validity was tested on the monthly mean temperature of two years data (2004 and 2005). Measured and predicted values for the monthly mean temperature were tested graphically. Various statistical techniques such as descriptive statistics and correlation coefficient were employed to analyze the data.The mean and standard deviation for the measured and predicted values were also calculated and compared.The differences in standard error between the measured and predicted values is ±0.01 and the correlation coefficient of over 90% was obtained. These show that the model is valid and can be used to predict future monthly mean temperature in Ilorin and other location with the same climatic condition with high accuracy.