This weekend marks the unofficial beginning of summer, so CNBC.com looked at how the stock market has historically performed leading up to Memorial Day and during the months that follow.
In the past 20 years, the major U.S. indices have been, on average, relatively flat in the week prior to Memorial Day. In recent years, however, they have been slightly negative.
A week after Memorial Day, all three indexes posted a gain, with the NASDAQ showing the biggest average gain, up 1.42 percent.
Within a month, those gains fizzled for the S&P 500 and Dow, both turning negative returns. And in recent years, those losses have accentuated, down about 2 percent or more.
On the other hand, the NASDAQ Composite managed to post a gain of 0.37 percent in the past 20 years.
During the summer months, the NASAQ Composite has the largest average increase over the past 20 years, up 3.19 percent.