The Worst Months Of The Year To Invest In The Stock Market

When it comes to investing, you may have heard the phrase "time in the market beats timing the market." The basic idea is that you will ultimately make more money in financial markets through consistent steady investments than you will trying to perfectly time a trade for maximum profits. This is where the idea of dollar-cost averaging comes into play — in which you consistently invest the same amount of money into an asset regularly, regardless of how well it's faring financially. However, while the general consensus behind this idea is that markets are largely unpredictable, and thus almost impossible to predict, there is something to be said for certain months of the year performing worse than others.

In fact, data shows that, historically, some months are better for investing than others. For example, the worst months to invest in the largest stock market indexes — like the S&P 500, Nasdaq 100, and the NYSE (New York Stock Exchange) – are June and September, according to tracked data from TradeThatSwing. However, there is more to the story than this, as each individual index has their own particular months to avoid.

TradeThatSwing data of the average performances of stock market indexes over the last 20 years found that, for the NYSE, the overall top worst months to invest were June, August, and September. However, it is also worth noting that while not the absolute worst, January, February, and May have also been historically weaker performing months for this index. As for the S&P 500, June and September were the worst, while January has historically been a weaker performing month. Meanwhile, the Nasdaq's worst months have been February, June, and September. 

However, when you look at only the last 10 years of performance, things change for these indexes. For example, in the last 10 years, the worst months for the S&P 500 were September and December, while for the Nasdaq, they were February, September, and December – with December being a new addition for both. The worst months over the last decade for the NYSE were February, March, August, and September, with March being the only new addition to this list.

Despite the data, it is worth noting that these months are not guaranteed to be negative during 2025 and beyond. Similarly, some months historically experience positive performance, though its not always guaranteed.

For the NYSE, when looking at the last 20 years, experienced up months in March, April, July, October, November, and December. However, in the last 10 years, up months were primarily April, July, October, and November. Meanwhile, during the last 20 years the S&P 500 has experienced positives during February March, April, May, July, August, October, November, and December. Yet, in the last 10 years, December was removed from this list, while June was added. For the Nasdaq, January, March, April, May, July, August, October, and November have shown strong performances throughout the last 20 years, while in the last 10, similar to the S&P 500, June was also added to the list.