Investors considering the S&P 500’s seasonal strength have an immediate question: will September’s inflation report show easing price pressures before the window opens?[1][3]
The proposed October 31, 2026–July 22, 2027 window has a favorable precedent: the index finished higher over those seasonal dates in all 15 selected midterm-election years from 1966–2022. Broader histories include losses, however, making the choice of years important to interpreting that record.[3]
The inflation benchmark
BEA’s September report is due October 29 at 8:30 a.m. EDT; its figures are unknown. The September 30 release reported August year-over-year PCE inflation of 3.4%, or 3.0% excluding food and energy. These provide the comparison for September. That release incorporated annual revisions beginning January 2021.[1]
August PCE inflation
Reported change from August 2025 to August 2026
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| Measure | Value | Period | Status |
|---|---|---|---|
| Headline PCE | +3.4% | August 2026 versus August 2025 | reported |
| PCE excluding food and energy | +3% | August 2026 versus August 2025 | reported |
What the midterm record establishes
TradeWave’s selected seasonal record shows a 17.63% median full-window increase. It describes index-level changes across selected midterm years, not consecutive years or expected returns from today. The S&P 500 is a spot index that cannot be invested in directly; these changes do not establish attainable profits from futures, options or exchange-traded products.[3]
The year-by-year seasonal record
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| Window starting year | Ending price change | Highest from entry | Lowest from entry |
|---|---|---|---|
| 1966 | +16.87% | +18.77% | -1.63% |
| 1970 | +18.68% | +26.45% | -1.53% |
| 1974 | +23.75% | +30.69% | -13.22% |
| 1978 | +9.06% | +12.90% | -1.48% |
| 1982 | +24.67% | +26.67% | -1.90% |
| 1986 | +26.43% | +28.94% | -3.47% |
| 1990 | +25.95% | +28.70% | -0.79% |
| 1994 | +17.84% | +19.18% | -6.24% |
| 1998 | +22.43% | +27.77% | -0.47% |
| 2002 | +11.56% | +14.64% | -10.94% |
| 2006 | +11.87% | +12.91% | -1.23% |
| 2010 | +13.56% | +15.72% | -0.96% |
| 2014 | +4.76% | +5.78% | -2.25% |
| 2018 | +10.08% | +11.29% | -13.47% |
| 2022 | +17.63% | +18.25% | -4.49% |
Explore this exact seasonal window in TradeWave. Compare its win rate and average result across different histories, and inspect how far prices moved above or below their starting point. Account access applies in TradeWave.
A positive finish can conceal discomfort
The yearly range chart shows each year’s same seasonal period, not the whole calendar year. October 31, 2018–July 22, 2019 is useful because its 10.08% ending gain coexisted with a move 13.47% below the starting level. The highs and lows reveal movement endured inside the window, without establishing their order, a peak-to-trough drawdown or a future stop.[3]
What happened inside each seasonal window
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| Window starting year | Ending price change | Highest from entry | Lowest from entry |
|---|---|---|---|
| 1966 | +16.87% | +18.77% | -1.63% |
| 1970 | +18.68% | +26.45% | -1.53% |
| 1974 | +23.75% | +30.69% | -13.22% |
| 1978 | +9.06% | +12.90% | -1.48% |
| 1982 | +24.67% | +26.67% | -1.90% |
| 1986 | +26.43% | +28.94% | -3.47% |
| 1990 | +25.95% | +28.70% | -0.79% |
| 1994 | +17.84% | +19.18% | -6.24% |
| 1998 | +22.43% | +27.77% | -0.47% |
| 2002 | +11.56% | +14.64% | -10.94% |
| 2006 | +11.87% | +12.91% | -1.23% |
| 2010 | +13.56% | +15.72% | -0.96% |
| 2014 | +4.76% | +5.78% | -2.25% |
| 2018 | +10.08% | +11.29% | -13.47% |
| 2022 | +17.63% | +18.25% | -4.49% |
Broader histories temper confidence
TradeWave checks consecutive histories to test whether favorability extends across all years: median results were 10.34% for 2016–2025 and 9.86% for 2006–2025, both with losses. These remain favorable but temper the perfect, limited midterm sample. The shorter comparison reuses 2018 and 2022; the longer also reuses 2006, 2010 and 2014 and contains the shorter history, limiting independent confirmation and any election-based explanation.[3]
See the history behind this comparison
TradeWave checks the same seasonal dates across different sets of years. This helps show whether the pattern holds up when you look at another stretch of history.
| History | Observed start years | Direction | Success rate | Median result |
|---|---|---|---|---|
| Article study: 15 selected midterm-election years (1966–2022) | 1966, 1970, 1974, 1978, 1982, 1986, 1990, 1994, 1998, 2002, 2006, 2010, 2014, 2018, 2022 | long | 100.0% | 17.63% |
| 10 consecutive historical windows (2016–2025) | 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024, 2025 | long | 90.0% | 10.34% |
| 20 consecutive historical windows (2006–2025) | 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020, 2021, 2022, 2023, 2024, 2025 | long | 85.0% | 9.86% |
Some years appear in more than one group, so agreement is not an independent test. A requested lookback can extend beyond available history; the observed years are listed above. Election-cycle groups use matching phases, not consecutive years. Results follow the direction shown: a positive short result means prices fell. Small samples and different market periods make the comparison less conclusive.
Inspect the range before entry
After the inflation update, inspect this same window’s outcomes in TradeWave. Recorded index levels end October 23, 2026, so they cannot establish entry conditions. The chart below superimposes the engine’s normalized seasonal overlay using this article’s 15 selected midterm years. Its next 60 weekdays, October 26, 2026–January 15, 2027, illustrate historical shape on a separate, shorter horizon than the full window. Those future dates represent neither recorded prices nor a forecast or target.[3]
Price history and the seasonal outlook
Explore this exact seasonal window in TradeWave. Compare its win rate and average result across different histories, and inspect how far prices moved above or below their starting point. Account access applies in TradeWave.
About this seasonal analysis
15 selected midterm-election years (1966–2022). The selected dates, years, direction, returns and ranges come from TradeWave. When a window boundary is a weekend or market holiday, TradeWave uses the next available trading session. SMN displays the returned results without recalculating them. A year label identifies the start of the historical window; a window can end in the following calendar year.
Green and red bars show the underlying adjusted-price movement. The range endpoints measure changes from the entry price, not a peak-to-trough loss. Historical results are before trading costs and do not guarantee future performance.