Note from dshort: I've updated this post at a reader's suggestion to include medians as well as means (averages) for the monthly performance.

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Oh, it's a long, long time from May to December,
But the days grow short when you reach September.
When the autumn weather turns the leaves to flame,
One hasn't got time for the waiting game.

The classic American pop standard September Song debuted in 1938. The Dow turned in a good month that year, up 1.57%, but over the decades, September has developed a naughty reputation in market lore.

This year the month is off to a particularly bad start, down 3.21% in the Dow and 3.69% in the S&P 500 in the first two days alone. Europe, three days into the month, is faring much worse, with the FTSE down 5.41%, the CAC 40 down 7.90%, and DAX down a stunning 9.31%.

With two down and nineteen market days left in September (and in the spirit of market trivia), let's survey the melody of the months in the Dow since October 1928, the point at which the index was expanded from 20 to 30 stocks. Here are the monthly medians and means (averages).

Yes, over the years, September has earned the distinction of the most melancholy voice in the chorus. But this fact, taken out of context, obscures an incredible range of performance.

The chart above shows the distribution from low to high. Let's close with a look at the 82 Septembers in chronological sequence.

Like all the calendar months, September's song has oscillated between major and minor keys in seemingly haphazard fashion. The economy may pencil in some lyrics, but the market will play its own tune. Let's hope this month's melody ends on a high note.