Bitcoin is beating its worst month on the calendar, but the last time it pulled off this same trick it crashed 23% in the quarter that followed. Two factors in October will decide whether 2026 ends in profit or loss.
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Bitcoin (CRYPTO:BTC) has lost money in eight of the 13 Septembers since 2013, and its average monthly return is a loss of about 2.9%, the worst of any month on the calendar, according to CoinGlass. That record is why traders call September Bitcoin’s toughest month. This year, the Bitcoin price closed August at $78,563 and trades at $81,214 as of September 19, 2026, up about 3.4% so far this month.
The gain comes despite a turbulent few weeks, in which Bitcoin dipped to around $76,000 after the Senate voted down a motion to advance the CLARITY Act on September 15 and the Fed raised rates by 25 basis points on September 16. However, by September 18 it had rebounded above $81,000. So the question for Bitcoin holders heading into October is whether a September gain like this one points to a strong fourth quarter.
Has September Stopped Being Bitcoin’s Worst Month?
September earned its “worst month” reputation in one five-year streak. The Bitcoin price lost value every September from 2017 to 2021, including a 13.4% drop in 2019, as reported by CoinGlass. Those five years dragged the 13-year average down to a loss of around 2.9%, and they’re why traders coined the term “Red September.”
However, Bitcoin has closed higher in each of the last three Septembers. It gained 3.9% in 2023, 7.3% in 2024, and 5.2% in 2025, so this year’s 3.4% gain continues a trend that is now four years old rather than breaking one. The losing pattern has not held since 2022, which makes it a weak reason to expect a loss in 2026.
The bigger problem is the sample. Thirteen years is a short record, and a single bad year can move the average by a full percentage point, so the average return for any month tells a holder little about the month ahead.
Bitcoin Fell to $76,000 and Climbed Back in the Same Week
The September rally was hard-earned. The Bitcoin price had been turned back at $82,000 four times since August 25, and then bad news came on two straight days. On September 15, the Senate voted 49-50 against advancing the CLARITY Act, the bill that would have set federal rules for the crypto market.
The next day, the Fed raised rates to a range of 3.75% to 4.00%, its first hike since 2023, and Bitcoin dropped to about $76,000 and held there.
Investors pulled $450 million from spot Bitcoin ETFs on September 15 alone, the largest single-day withdrawal since June 25, per SoSoValue. That came after strong inflows of around $3.8 billion over the three weeks to September 5, so the same buyers who carried August were selling in the week the price needed them most.
Then the price turned, and Bitcoin climbed from $76,400 on September 17 to $81,702 a day later. Most of that rebound came from short sellers, the traders who had bet on a fall, being forced to buy back as about $300 million in leveraged positions were liquidated in four hours. Forced buying makes a thinner rally than new money, so the next two weeks of ETF flows will show whether new buyers followed.
A Green September Came Before a 23% Drop Last Year
Bitcoin’s own history argues for a strong fourth quarter. The Bitcoin price closed September higher in 2015, 2016, 2023 and 2024, and in each of those years the fourth quarter finished in the green as well, with gains of 57% in 2023 and 48% in 2024, according to CoinGlass. That record is where October’s “Uptober” nickname comes from, since it is Bitcoin’s strongest month on average.
However, last year broke that trend. Bitcoin rose 5.2% in September 2025, then fell 23.1% in the fourth quarter, its second-worst on record behind 2018. The slide started in October 2025, Bitcoin’s first red October since 2018, after a tariff threat from President Trump triggered about $19 billion in liquidations on October 10, and the price never made that ground back before December 31.
So the record shows four wins and one loss, and the loss is the freshest. The reason it failed last year tells you more than the four wins do. Bitcoin turned down in the fourth quarter of 2025 when ETF buyers stopped buying and leveraged traders got wiped out, and both are back in play this month, as the outflows and the short squeeze above show.
On top of that, the Fed’s September projections show 12 of 18 officials expect rates to end 2026 higher than they are today, which means at least one more hike at the October 27-28 or December 8-9 meetings. Bitcoin held through one hike this month, and it could face another before December.
What Does a Green September Say About the Bitcoin Price in Q4?
A green September alone says little about the fourth quarter. Bitcoin held up through a rate hike and a failed bill, but the month lost its curse three years ago, and the last green September led straight into a 23% quarterly loss. Our view is that two things could decide the quarter: whether ETF inflows return in October after August’s $3.5 billion, and whether the Fed hikes again on October 28.
Bitcoin needs a 7.7% gain from $81,214 to close 2026 above its $87,497 starting price, so the fourth quarter decides whether 2026 ends in the red. If ETF inflows return and the Fed pauses, that gain could arrive before December. If the flows stay negative and the Fed hikes again, a green September might mean what it meant in 2025, and the Bitcoin price could end the year below where it started.
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