The best month of the year for the yellow metal is coming up. : September is shaping up to be a good month for gold GC00, +0.18%. That’s because there’s an additional factor in bullion’s favor in September: seasonality. Since 1973, when gold began trading freely, September has been the best month of the year, on average, for the yellow metal. The chart below plots the data. Gold’s average September return has been 1.8%, more than double its all-month average of 0.8%.