The purpose of this article is to investigate wind turbine production, the variability of that production, and the relationship between output and system-wide demand. A review of the literature reveals that a variety of measures (and methods) to explore the variability of wind power production exist. Attention then turns to the province of Ontario (Canada), and the performances of four wind farms are examined for 2006 and 2007. Key conclusions include that the wind farms' capacity factors vary from 27.6% to 35.6%, with higher values in winter as compared to summer; wind power performs better than the seasonal average during peak periods; wind is a better "partner" for the Ontario electricity system in the winter as opposed to the summer; and the increased geographic distribution of wind farms decreases their collective variability. (Contains 8 tables, 14 figures, and 6 notes.)