What are the two worst months for stocks?

When the Market Tends to Wobble

While the stock market has historically delivered strong long-term gains, not every month is created equal. If you're looking at short- or medium-term returns, timing can sometimes feel like it matters — and history offers some clues. September consistently stands out as the weakest month for stocks.

Since the early 20th century, September has, on average, posted more negative returns than any other month. While the reasons vary — everything from seasonal portfolio rebalancing to investor psychology — the pattern persists across decades. It’s not a guaranteed downturn every year, of course, but the trend is hard to ignore.

That said, it’s not the only month worth watching. October has its own reputation, thanks in part to dramatic crashes like those in 1929 and 1987. Though October has occasionally seen sharp recoveries, its volatility leaves a lasting impression. Meanwhile, summer months like June and August can also bring turbulence, especially when geopolitical tensions rise or earnings reports fall short.

Still, it’s important not to overreact. These patterns are based on averages, and markets often defy expectations. A weak historical month doesn’t mean investors should head for the exits — many downturns in September, for example, were followed by strong rebounds.

What matters most isn’t timing the calendar, but staying aligned with your long-term strategy. Market dips, whenever they happen, can even present opportunities for patient investors. But if you're sensitive to short-term swings, knowing the historically shaky months might help you brace for potential bumps — not panic when they arrive.