August Isn’t the Problem — September Is the TestS&P 500SP_DLY:SPXTradeSentinelNotesMidterm Seasonality: August Isn’t the Problem — September Is the Test The midterm-year table gives a cleaner roadmap than simply saying “August and September are bad.” What the data actually says: August is not consistently bearish. Its average return is only -0.22%, and 64% of midterm-year Augusts were positive. What makes August notable is volatility: it has the highest dispersion of any month in the table. September is the real weak spot: Average return: -2.06% Positive only 43% of the time Then the pattern flips. October Average: +3.62% Positive 71% High volatility → often a reversal month November Average: +2.25% Positive 79% Much lower volatility → often the cleaner continuation month December Essentially neutral on average at -0.01% What matters now This fits the current TradeSentinel readings unusually well: volatility remains very low SMA20 breadth has fallen toward 50% Nasdaq new highs and new lows are almost equal long-term SMA200 breadth is still healthy So the question is not: “Will August sell off?” It is: Does today’s short-term deterioration repair before September, or does it become the start of the historical midterm washout? The two paths Bullish repair Breadth recovers → new lows contract → SPX/NDX reclaim short-term trend → volatility stays contained. Bearish deterioration Breadth stays below 50% → new lows dominate → SMA50 breaks → VIX/VIX3M moves toward 1 → September weakness gains credibility. TradeSentinel Takeaway August is the instability window. September is the real stress test. October is where reversals often begin. November is historically the cleaner momentum month. The goal is not to predict the seasonal pattern. It is to let breadth, leadership and volatility tell us whether 2026 is actually following it.