Collectors repeat a seasonal catechism: prices dip in January when card money becomes rent money, sag through summer, and rip upward for the holidays. Our index can finally test it, and the test comes back mostly negative, for a humbling reason. In nineteen months of Moonstone Pokemon Index history, February 2025 through August 2026, there is not one negative month. The market went up in the alleged January trough, up in the alleged summer doldrums, up in every month we have measured.
Moonstone Pokemon Index, monthly average
The seasons show up anyway, as fast and slow
A market that never falls can still have rhythm, and this one does. The two slowest months on the tape are exactly where folklore predicts weakness: January 2026 at +1.8% and November 2025 at +2.2%. The hottest stretch is spring into early summer 2026, three straight months between +8.5% and +8.9%, with August 2025 (+7.7%) the prior peak. So the seasonal story survives in miniature: the January effect is real, it just meant decelerating instead of declining, because an overwhelming bull trend swamped it.
That is also the honest limitation of this study. Nineteen months is one market regime, and it happened to be a historic one. We cannot tell you what Pokemon seasonality looks like in a flat market, because our index has never seen a flat market. What we can tell you is that anyone who waited for the traditional January dip to buy in 2026 paid 1.8% more instead, and anyone waiting for a summer lull watched the fastest quarter on record.
Moonstone Pokemon Index, weekly points from February 24, 2025 (=100) through August 26, 2026 (231.4), averaged by calendar month; month-over-month changes computed on those averages. The index aggregates verified market prices of its fixed constituent set, the same series charted on the Moonstone homepage. Nineteen months covers a single sustained bull regime; no claim here extends to other regimes. Not financial advice.