Over a period of years, the monthly mean mileage of wind per day during the six months, April to September, at four meteorological stations in central and southern Alberta and Saskatchewan is greatest in April and May, and least in July and August. In all cases the range of variation of the monthly means is considerable, being of the order of 50%. Significant correlation in the inter-annual fluctuations at the four stations is not demonstrable from the available data, but there is some indication of correlation between the mileages at a given station in successive months of the same year. During the season as a whole, northwesterly winds predominate, but in this respect also there are pronounced annual variations.Variation in the amount of wind from day to day within months is also pronounced, and tables are presented showing for each of the six months the relative frequency of occurrence of different daily mileages.On the whole, more wind is recorded during the daytime than at night. The hourly averages for all six months show a definite diurnal trend, the maximum being in the vicinity of 3 p.m., but the actual hourly sequence on a given day may deviate markedly from this underlying regularity. There is a slight tendency for days of above-average temperature to have a higher wind mileage, but this is a minor factor in comparison with the uncorrelated variation of both quantities.