October has risen for Bitcoin in ten of the past thirteen years, a 77% hit rate the market has nicknamed Uptober.
Bitcoin rises in 55% of all months. Measured against its own baseline rather than a coin flip, ten of thirteen is not a statistically significant result.
And if you test every month, there is roughly a two in three chance that one of them looks this good by accident.
What the Number Actually Says
Across the 165 months of Bitcoin’s recorded history, the asset finished higher in about 55% of them and averaged 9.70% a month. That is the comparison Uptober has to beat, because an asset that rises most months will rise in most Octobers whatever the season.
At a 55% base rate, thirteen Octobers would be expected to produce around 7.2 positive months. Ten were positive. The excess is under three months spread across thirteen years.
A binomial test on ten of thirteen against that 55% baseline returns a probability of about 0.09. Against a 50% baseline it is 0.046, marginal at best. Neither clears the bar anyone would apply to a drug trial.
The Twelve-Month Problem
The more serious flaw is how the pattern was found. Nobody nominated October in advance. It was identified by looking at a calendar of twelve candidates and keeping the one that performed.
If every month were statistically identical, the chance that at least one of the twelve would show a run as strong as October’s is roughly 69%.
That is the whole of Uptober. A pattern of this strength is what you should expect to find somewhere in the year, by chance, in most years you care to look. It is not evidence that October is different. It is evidence that twelve is enough attempts.
Last October Fell
The most recent October was down 3.7%.
The gains that build the reputation are concentrated and mostly old. October 2021 returned 39.9% and October 2023 returned 28.5%. October 2016 added 15.2%, 2024 added 10.8% and 2022 added 5.6%. Two outliers carry most of the average in a sample of thirteen.
A mean propped up by two observations is not a base rate anyone can position against.
The Same Data Argues Both Ways
The seasonal case is usually presented alongside on-chain readings that point the other way, taken from the same analysis.
Unrealized profit across the network has reached 33%, the highest since December 2024, and profit-taking has hit 25,700 BTC, the most this year. Both figures come from the analytics firm CryptoQuant, whose head of research Julio Moreno has described spikes of that kind as “typical of a rally losing steam and at risk of a deeper correction.”
One half of that dataset is being used to argue the month will be strong. The other half says the rally is extended.
There may be sound reasons to be constructive on Bitcoin this October. The calendar is not one of them.
