History Says the Stock Market's Best 6 Months Start Nov. 1. Here's How Often They've Paid Off Since 1950.

The stock market's best six-month period seems to begin around November 1, according to Wall Street's "sell in May and go away" adage. This theory suggests the optimal time to own stocks spans from November through April. In 1950, Jeff Hirsch and his father, Yale, popularized this pattern in the Stock Trader's Almanac. This year, November 1 falls on a Sunday, so the initial trading day for this period is Monday, November 2, starting from the close on Friday, October 30.

The S&P 500 (^GSPC) begins this stretch at 7,676.77, approximately 1.8% below its October 6 record close of 7,818.93.

To examine the validity of this saying, I analyzed the index's daily closes from 1950 to the present, focusing solely on price fluctuations without dividends. The S&P 500 increased in 58 out of the 76 stretches spanning from the last close of October to the last close of April. On average, these periods yielded a gain of around 7%.

In contrast, the remaining six months from May to October saw the index rise in 50 out of 76 years, averaging a gain of about 2%. This significant disparity in performance amounts to a substantial difference when compounded over time. For instance, if $1 were invested in the index during all 76 November-to-April stretches, it would have grown to approximately $117 based solely on price appreciation.

Conversely, investing $1 in the June-to-October periods would have only resulted in a value of around $3.40. Thus, the majority of the index's price gains since 1950 have occurred during the November-to-April half-year. However, the summer months, often regarded as unfavorable, have climbed in around two out of three instances. Despite these gains, selling in May would have required investors to miss out on a substantial number of positive stretches.

Of the 18 losing stretches, 11 finished below a 5% decline, with an average loss of roughly 6.5%. Six stretches actually resulted in losses exceeding 17%. These included significant declines from October 1973 to April 1974 and 1969 to 1970, as well as other notable drops from October 2000 to 2001, 2007 to 2008, 2021 to 2022, and 2008 to 2009, all of which coincided with bear markets that drove the index at least 25% below a record close.

These drops were primarily driven by factors such as interest rates and company earnings rather than the specific month. Additionally, the final figures may not fully capture the volatility of these periods. For example, the stretch ending in April 2009 saw the index decline by around 10%, even though it had already lost approximately 30% by its March 9, 2009, low.

Similarly, the stretch ending in April 2020 saw a decline of about 4%, despite a 26% drop by March 23, 2020, and the most recent miss from October 2024 to April 2025 ended down around 2%, following a 13% decline by April 8, 2025. Even the gains observed in the recent November-to-April period were accompanied by brief setbacks. The index increased by approximately 5% from October 2025 to April 2026, but it experienced a decline of around 7% at its lowest point in late March.

Despite these fluctuations, the November-to-April stretch has still managed to outperform in 50 out of the past 76 years. This historical data suggests that while the November-to-April period is the market's best six-month window, the six less favorable months should not be entirely dismissed. For long-term investors, buying an S&P 500 index fund during the weaker months like May through October could be a prudent strategy, especially considering the strong performance observed in the November-to-April period.

The summer months, despite their mixed reputation, have still delivered gains in 50 out of the last 76 years.