bitcoinseasonality

$BTC | Is September really Bitcoin's worst month, or is August the one to watch? The two answers disagree depending on which number you use. September has the lower average return. August has the better average but a far worse median and the worst win rate of any calendar month. That gap matters more than the label.
## What does "worst month" actually mean?
On the desk we never trusted an average without checking the median behind it. SatoshiMacro's monthly returns heatmap tracks every calendar month of Bitcoin price history in AUD terms since 2013, and across 2014 to 2025 the headline numbers for the two weakest months read almost the same at a glance. September averages -1.9 percent with a -1.3 percent median and closes positive in 6 of 12 years, exactly 50 percent. August averages a slightly milder -1.0 percent, yet its median is -8.3 percent and it has closed positive in only 3 of 12 years, a 25 percent hit rate. One of those months is consistently mediocre. The other is bimodal.
## Why the mean and the median disagree so sharply in August
Here is the specific reason. August 2017 returned plus 67.4 percent, the second best single month in the entire AUD dataset behind only May 2017's plus 70.4 percent. That one outsized rally drags August's twelve year average most of the way back toward zero while doing nothing for the typical August, which the median shows was a losing month three years out of four. September has no equivalent outlier in either direction. Its distribution is narrower, and its average and median tell roughly the same story. If you are sizing a position around "the weak month," August is the one where the average lies to you.
## What this means for cycle top timing
The heatmap's own FAQ makes an honest admission worth repeating: prior Bitcoin cycles peaked in November or December, but the current cycle broke that pattern. Its highest daily close so far sits at A$187,780 on 13 August 2025, not in the traditional fourth quarter window, and the price has since drawn down heavily from that level. Seasonality predicted a Q4 top. It did not show up on schedule. My read is that calendar patterns describe what usually happens across three visible cycles, not what will happen in this one, and three cycles is a small sample for any timing conclusion.
## Should October still get credit as Uptober?
Yes, with a caveat. October is the strongest calendar month by every measure the heatmap tracks: plus 16.8 percent average, plus 15.9 percent median, and a 75 percent win rate across 2014 to 2025, the best combination of any month. But "mostly" is the honest word. The page flags three negative Octobers in that window, in 2014, 2018 and 2025. When I size anything around a calendar effect, I size it like background noise sitting underneath the real catalysts (halvings, ETF flows, macro liquidity), never as the thesis itself.
## Does any of this change what you actually pay tax on?
This is where the Australian angle matters, and where seasonality data quietly runs out of road. The heatmap shows raw AUD price returns, not after tax returns, and the two are not the same thing. If you are holding past the ATO's 12 month mark to qualify for the 50 percent CGT discount, a weak September or a strong October changes your paper position, not your tax timing. SatoshiMacro's CGT calculator models the discount separately from price action for exactly this reason, because the two questions, when did the price move and when does my holding period reset the discount, have different answers and get confused constantly in year end planning.
## The bottom line
Across 144 months from 2014 to 2025, 80 closed positive, 55.6 percent, for an average monthly return of plus 5.55 percent. Nine of the twelve calendar months carry a positive average. That is a genuinely favourable base rate, not a reason to treat any single month as predictable. September's average is weak but stable. August's average flatters a month that is actually worse than it looks. October earns its reputation in most years, though not every year. Past performance here is exactly that, past performance: a statistical tendency with a small sample caveat attached, not a signal you trade on its own.
https://satoshimacro.com/tools/crypto/cycle-indicators/bitcoin-monthly-returns-heatmap/?utm_source=binance_square&utm_medium=social&utm_campaign=autopilot_article
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