Is it altcoin season? Our altcoin season index, and what came after it
Today 32 of our 50 most traded altcoins beat Bitcoin over the last 90 days: an altcoin season index of 64 (neither; 75 or over is altcoin season, 25 or under Bitcoin season). On the 228 days since 2019 it read 75 or over, the 50 coins did −15.9% against Bitcoin over the next 90 days on average, ahead of it 18% of the time; after the other days, −0.1%. The altcoin seasons came in 9 separate stretches: no band is clear of luck (a luck test of 3 with both halves of the days agreeing). Past patterns, not financial advice.
as of · our daily closes, Jul 2, 2019 to Oct 14, 2026
An altcoin season index asks one thing: of the biggest altcoins, how many did better than Bitcoin over the last 90 days? Ours takes the 50 most traded coins on our record each day (by dollar volume over the 30 days before; stablecoins, wrapped coins and Bitcoin itself left out) that already traded 90 days earlier. 75 or more of every 100 ahead of Bitcoin is an altcoin season; 25 or fewer, a Bitcoin season.
Oct 14, 2026: 64, neither. 32 of 50 coins did better than Bitcoin, which moved +28.0% over the 90 days.
the indexaltcoin season, 75 and overBitcoin season, 25 and under
Put the index on your site
Two lines anywhere in a page show today's reading and its last year, updated daily, with the link back here (more):
as of · the same coins against Bitcoin, from the reading day's close
After each day, an equal stake in that day's 50 coins against holding Bitcoin over the next 30 and 90 days, bought at that day's close (a coin that stopped trading counts its last close).
Index
Days
Stretches
Next 30 days
Next 90 days
altcoin season 75-100
228
9
−2.1%32% ahead
−15.9%18% ahead
neither 26-74
1,672
23
−2.2%38% ahead
−3.5%33% ahead
Bitcoin season 0-25
729
24
+1.3%53% ahead
+7.4%48% ahead
every day
2,632
—
−1.2%42% ahead
−1.5%36% ahead
Days and stretches count the days with 30 days after them; a stretch ends after 7 days out of its band. Each band against all the other days over the same hold, with its luck test under it (✓ past the bar, both halves of the days agreeing; the halves on hover):
Index
Next 30 days
Next 90 days
altcoin season
−1.0% t −0.2
−15.8% t −1.2
neither
−2.8% t −0.9
−5.3% t −0.6
Bitcoin season
+3.5% t 1.0
+12.4% t 1.2
After an altcoin season (75 or over, 228 days in 9 separate stretches, the last on Oct 5, 2026) the altcoins did −15.9% against Bitcoin over the next 90 days on average, ahead of it 18% of the time: −15.8% against the other days, −25.5% in the older half of the days and −15.1% in the newer. A luck test of −1.2, not past the bar of 3.0.
After a Bitcoin season (25 or under, 729 days in 24 separate stretches, the last on Apr 6, 2026) the altcoins did +7.4% against Bitcoin over the next 90 days on average, ahead of it 48% of the time: +12.4% against the other days, +15.4% in the older half of the days and +7.8% in the newer. A luck test of 1.2, not past the bar of 3.0.
When Bitcoin makes a new high, do the alts follow?
The same coins against Bitcoin after the 72 days Bitcoin closed above every close before it, with a year of closes behind it (the last on Oct 6, 2025), against the other days:
The next 30 days: the altcoins did +10.1% against Bitcoin on average (72 days in 16 separate stretches), ahead of it 60% of the time: +11.6% against the other days, +27.4% in the older half of the days and −1.4% in the newer. A luck test of 1.5, not past the bar of 3.0.
The next 90 days: the altcoins did +35.4% against Bitcoin on average (72 days in 16 separate stretches), ahead of it 46% of the time: +38.0% against the other days, +106.8% in the older half of the days and −18.7% in the newer. A luck test of 1.5, not past the bar of 3.0.
§ 03 · How it is tested
How it is tested
as of · methodology
A luck test (t) says how far a result sits from zero, in units of its own noise: about 2 is rarely luck for one test, but many tests at once need more, which is what the first cut is for.
Every day with a reading is a stake at that day's close in the coins that made it. Neighbouring days share most of their 30 or 90 days, so the luck test does not count them as fresh evidence: each calendar day weighs in by how many of the band's holds, and of the other days', cover it, so a band counts as the holds that share no day, and each band is set against all the other days over the same hold. The averages on this page use every day. With 6 tests (three bands, two holds), a result needs a luck test of 3.0 or more and both halves of the days on its side. Seasons come in stretches: a few hundred days can be a dozen holds that share no day.
Our record holds today's coins: altcoins that later vanished are missing from the early years, which makes the index read higher and the altcoins look better against Bitcoin, never worse. Moves are before trading costs and funding.
§ 04 · Revisions1 dated
Revisions
as of · every change to its headline numbers, dated
This study is re-run every night on the whole history. It was first written on Oct 15, 2026; its numbers last moved on Oct 15, 2026. Each night its headline numbers moved is listed here, newest first.
the altcoins against Bitcoin over the next 90 days, against the other days: after altcoin season −16% · after Bitcoin season +12%