If you listen closely, you’ll hear gold investors whispering that “it’s an ill wind that blows no good.” That’s because, while September may be the worst month of the calendar for stocks, it’s the best month for gold. Since it began trading freely in the U.S. in the early 1970s, gold bullion GCZ8, +0.40% has produced an average gain of 2.1% in September. The comparable monthly average for all non-September months is 0.6%. (See chart.) This difference is significant at the 90% confidence level that some statisticians use when determining if a pattern is real — though not at the more stringent 95% confidence level.via