No difference

The "full moon makes markets wild" folklore

Trading folklore has long held that full and new moons mark turning points, and moon-phase chart indicators abound. Academia has tested "lunar phases and stock returns" seriously — a few papers in the 2000s reported small correlations, but later large-scale replications mostly failed to reproduce them. This page runs that question automatically, every day, for two major currency pairs (USD/JPY and EUR/USD).

How this verdict is computed

• Data: the European Central Bank's daily reference rates (since 1999) — the widely cited official fixings
• We test the size of moves, not their direction: each trading day's absolute percentage change from the previous day
• FX volatility carries strong weekday patterns (Monday gaps, jobs-report Fridays), so each day is compared with the average for the same "weekday × month" combination — the same adjustment used on the births page
• Days are classified as full moon days (±24h around the instant) or new moon days using the moon age at the ECB fixing time (early afternoon CET); each group's mean index is compared with 1.00

See the methodology for the exact criteria.

Please note

• This page presents historical statistics, not investment advice. Even if a verdict ever moves away from "No difference," that would not imply a tradable edge (after transaction costs, a few percent of volatility difference has essentially no economic value)
• We make no claims about moon-phase trading systems. The only question tested here is whether currencies visibly move more on calendar full moon days

Sources

• ECB Euro foreign exchange reference rates (via the Frankfurter API)
• Moon phase instants computed in-house from Jean Meeus, "Astronomical Algorithms" (UTC)