U.S. stocks shine in October of midterm election years! The S&P 500 has historically averaged a 3% gain, with a 73.7% probability of rising.

Note that historical patterns from U.S. midterm election years show that stocks tend to post notable gains toward the end of the year. An analysis of monthly S&P 500 returns from 1950 to 2025 compiled by Carson Group found that October has historically been the strongest performer. The data show that October typically posts a 3.0% gain, rising 73.7% of the time in those years. November ranks second, with an average gain of 2.7% and a 78.9% probability of rising. The contrast with earlier months is striking. June is the weakest, with an average decline of 2.1% and gains only 36.8% of the time in midterm election years. September also tends to lag, with an average decline of 0.8% and gains in only 47.4% of samples. January and May likewise post modest average declines. March and July deliver smaller but positive average returns, while December typically rises 0.8%. As the next midterm election cycle approaches, these year-end patterns are drawing attention. Carson Group's Ryan Detrick highlighted the standout records for October and November. These data cannot guarantee any outcome for the current cycle, but they help explain why some market participants are starting to focus on positioning as the calendar shifts from September into a historically stronger window. Seasonality is just one of many variables, alongside valuation, policy and growth, but the long-term patterns of midterm election years remain a frequently cited reference for investors tracking the political calendar.