The Market’s Secret Calendar — and What It Means for the Rest of 2026

Here we are in the second week of 2026, staring down 11 ½ months of unknowns…

We don’t know what headlines we’ll get. We don’t know which CEO will say something dumb on an earnings call.

We don’t even know which “this time it’s different” narrative will blow up on social media.

But we do know how the market has tended to behave, month by month, over the last seven-plus decades…

Looking at the S&P 500 back to the mid-20th century, the long-term picture is clear…

U.S. stocks have compounded at roughly 10%–11% a year with dividends reinvested, depending on the period and dataset you use.

That’s the forest. Inside that forest, though, the trees — the individual months — have their own personalities…

Some months tend to be quietly positive, some are noisy and flat, and one in particular has earned a reputation as the market’s resident troublemaker.

This isn’t about fortune-telling. It’s about expectations.

If you know that certain parts of the year have historically been more volatile or stronger than others, you’re less likely to panic when the market is simply doing what it’s always done.

So let’s walk through the calendar and talk about what history says — and how to use it without turning your portfolio into a seasonal science experiment.

Winter’s Opening Gambit: January and February

January gets way more attention than it deserves…

There’s the “January effect,” small-cap folklore, tax-loss rebound chatter, and a lot of talk about how “as January goes, so goes the year.”

The data? Much less dramatic…

Over long stretches, January has delivered a modest positive average return, but it’s not consistently one of the star performers.

In fact, in more recent 20-year windows, January has actually been on the weaker side compared with other months.

Sometimes it’s strong, sometimes it’s soft — and that’s the point. If you put too much weight on a single month, you end up whipsawed by noise and headlines.

Then we’ve got February, the forgotten final stretch of winter…

Historically, it’s been a fairly average month — not usually a disaster, not usually a hero.

Over long datasets, it shows a slightly positive bias, but nowhere near the standout strength you see later in the year.

The right mindset for both January and February is simple: You’re setting the tone, not deciding the whole story.

For 2026, that means don’t overreact to whatever the market does in Q1…

If stocks wobble, that’s normal. If they pop, that’s normal too.

Your job is to keep adding capital on your schedule, not the market’s.

Spring Tailwinds: March and April

If winter is warm-up, spring is the first real acceleration lane…

Across multiple studies of S&P 500 seasonality, March and April consistently show up in the “better than average” camp.

April, in particular, has a strong historical reputation…

Many seasonality analyses going back decades flag April as one of the best months on average for U.S. stocks, with solid positive returns more often than not.

Now, that doesn’t mean April 2026 is guaranteed to be a winner — it just means that, historically, that’s when tailwinds have tended to show up.

Tax refund money, new-year allocations that trickle in over the quarter, and the way the earnings calendar lines up all play a part.

March is a little more temperamental but still leans positive in most long-term datasets.

And together, these two months help explain why, when you look at the first four months of the year as a block, the historical picture is generally favorable.

So if you’re planning for 2026, think of spring as a time when you want to be fully invested rather than sitting on the sidelines waiting for “a better entry.”

Historically, the better entry has often been behind you by the time you realize it.

“Sell in May”? The Myth, the Mess, and the Middle of the Year

Then comes May, the month that launched a thousand lazy headlines: “Sell in May and go away.”

The idea is that the six months from May through October have historically underperformed the November–April stretch.

And there is some truth in that if you look at very long datasets, the winter half often does edge out the summer half.

But here’s where a lot of investors go off the rails…

Even in the supposedly weaker half of the year, the market’s long-term average return is still positive. You do not see an automatic black hole from May through October.

You see more modest average gains and, yes, some extra chop — but also plenty of very strong years where summer and early fall delivered serious upside.

Historically, May itself has often been a decent month in more recent 20-year data, and June tends to be weaker but not consistently disastrous.

July actually shows up as one of the stronger months on average, with positive returns more often than not.

So for the core of 2026 — May, June, July — the lesson isn’t to run away. It’s to not let a slogan override a decade-long plan.

If anything, “Sell in May” often becomes a contrarian opportunity when too many people take it literally and dump perfectly good positions just because the calendar flipped.

The Market’s Problem Children: August and September

Now we get to the troublemakers. Ask any seasoned trader which month they instinctively distrust, and you’ll hear the same name: September…

According to CFRA data summarized by Reuters and other outlets, the S&P 500 has fallen by an average of about 0.6% in September since 1945, making it the only month with a distinctly negative average return over that period.

And when September is bad, it can be really bad — the average loss in down Septembers is several percentage points.

August doesn’t have quite as notorious a record, but it’s often grouped with June and September as one of the more challenging months in recent decades.

Low liquidity, vacations, and pre-fall positioning all contribute to the perception that late summer is a weird, jumpy time in the market.

So what does that mean for the back half of 2026?

It means you should expect some volatility around late summer and early fall.

And when you know that September has a long track record of being the weakest month on average, a rough patch doesn’t feel like the end of the world…

It just feels like history doing what history does.

For long-term investors, that’s often the window to put fresh cash to work, not the time to put everything in cash and go hide behind the couch.

Fall Fireworks and the Santa Rally: October Through December

Here’s the twist: The market’s worst month is immediately followed by one of its most surprisingly positive stretches.

October has a reputation for crashes because that’s when some of the most famous ones happened.

But if you look at long-term monthly averages, October actually leans positive.

In fact, in many seasonality studies, it lands in the “better than average” group rather than the doghouse.

Then come November and December — the market’s holiday power duo…

CFRA’s long-term data show that, while September has been the only clearly negative month on average since 1945…

November and December rank among the strongest, with solid average gains and high “win rates” (percentage of years with positive returns).

Other analyses echo the same story: November, in particular, often sits near the top of the leader board for average monthly returns.

This is the backbone of the so-called “year-end rally.”

You get positioning ahead of the following year, performance-chasing by funds that don’t want to be left behind, and good old-fashioned optimism that tends to show up as we roll into the holidays.

So, for the final quarter of 2026, that means one simple thing: You want to already be in the game when Q4 arrives.

Waiting until late November to “see how things look” is like walking into a movie premier for the last 20 minutes and wondering why everyone else is so excited.

How to Use Seasonality in 2026 Without Going Crazy

So where does all this leave you as we map out the rest of 2026?

First, remember the big picture. Over long horizons — decades, not months — the S&P 500 has delivered around 10%–11% a year with dividends reinvested.

That long-term wealth machine matters far more than whether September knocks a few percentage points off your account before the holidays.

Second, treat monthly patterns as context, not commands…

Knowing that September is historically weak and that November and December are historically strong can help you emotionally.

When volatility shows up in the late summer, you’ll recognize it as a feature, not a bug.

When the market rips higher into year-end, you’ll understand that this isn’t “weird” — it’s actually pretty normal.

Third, build a plan that doesn’t depend on you outsmarting the calendar…

Dollar-cost averaging into your favorite stocks, ETFs, and themes on a regular schedule is still one of the most powerful ways to harness all of this without trying to trade every wiggle.

Essentially, you’re letting history do the heavy lifting while you focus on saving, allocating, and staying calm.

So, as we move through 2026, there will be scary headlines, confusing months, and stretches where it feels like nothing is happening. But that’s OK.

The market’s calendar has looked lumpy and uneven for more than 70 years — and yet, through all of it, the long-term trend has been relentlessly higher.

Your job isn’t to predict what the market will do this March or next September.

Your job is to still own great assets when those months are long gone and the compounding has had time to work.

That’s how you beat the markets. That’s how you win this game. That’s how you retire in comfort.

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