All 7 USD-major pairs cluster their loudest 5 weekday half-hours inside Tue-Fri 12:30-14:30 UTC — 35 of 35 top-5 cells sit in the US-morning window (100%), closing the 7-day cross-family arc at 238 of 245 (97.1%) — and Fri 13:30 UTC (the NFP slot) is the loudest cell only for USDCAD
Across all 7 USD-major pairs (EURUSD, GBPUSD, USDJPY, USDCHF, AUDUSD, NZDUSD, USDCAD), 35 of 35 top-5 loudest weekday half-hours sit inside the Tue-Fri 12:30-14:30 UTC US-morning window. Every pair is 5-of-5 in-window. USD-majors are the third currency family with 100% concentration.
Seventh and final cross-family generalisation, closing the 7-day arc: JPY (33/35) → CHF (35/35) → AUD (33/35) → NZD (33/35) → EUR (34/35) → GBP (35/35) → USD-majors (35/35, today). 238 of 245 top-5 cells across the 7 families (97.1%) inside the Tue-Fri 12:30-14:30 UTC window.

Per-pair top-5
| Pair | Typ. cell | Top-5 (dow slot_utc median_pips) | Ratio | In-window / 5 |
|---|---|---|---|---|
| EURUSD | 9.35p | Thu 13:30 19.40; Thu 14:00 19.30; Thu 12:30 19.20; Fri 14:00 18.80; Fri 14:30 18.20 | 2.07x | 5 |
| GBPUSD | 11.40p | Thu 13:30 22.20; Thu 12:30 22.05; Fri 14:00 22.00; Fri 14:30 22.00; Fri 13:30 21.60 | 1.95x | 5 |
| USDJPY | 9.00p | Thu 13:30 17.00; Fri 13:30 16.60; Fri 14:00 16.30; Thu 12:30 15.90; Thu 14:00 15.80 | 1.89x | 5 |
| USDCHF | 7.60p | Thu 13:30 16.00; Thu 12:30 15.60; Fri 14:30 15.60; Fri 14:00 15.10; Thu 14:30 15.00 | 2.11x | 5 |
| AUDUSD | 8.50p | Fri 14:00 14.70; Fri 13:30 14.50; Thu 13:30 14.45; Fri 14:30 14.40; Tue 14:30 14.00 | 1.73x | 5 |
| NZDUSD | 8.10p | Thu 13:30 14.00; Fri 14:00 13.55; Fri 13:30 13.40; Fri 14:30 13.30; Thu 14:30 13.25 | 1.73x | 5 |
| USDCAD | 9.10p | Fri 13:30 19.75; Fri 14:30 19.60; Wed 14:30 19.10; Fri 14:00 18.80; Thu 13:30 18.75 | 2.17x | 5 |
Novel finding: Fri 13:30 UTC (NFP) is #1 only for USDCAD
The received wisdom says NFP is the loudest half-hour of the FX week. For USDCAD it is (Fri 13:30 UTC #1, 19.75p, edging out even the pair’s own Wed 14:30 UTC EIA-petroleum window). For every other USD-major, Thu 13:30 UTC (US weekly jobless claims) beats or matches NFP:
| Pair | Loudest cell | Fri 13:30 UTC (NFP) | Delta |
|---|---|---|---|
| EURUSD | Thu 13:30 UTC 19.40p (#1) | 17.90p (#6) | -1.50p |
| GBPUSD | Thu 13:30 UTC 22.20p (#1) | 21.60p (#5) | -0.60p |
| USDJPY | Thu 13:30 UTC 17.00p (#1) | 16.60p (#2) | -0.40p |
| USDCHF | Thu 13:30 UTC 16.00p (#1) | 15.00p (#6) | -1.00p |
| AUDUSD | Fri 14:00 UTC 14.70p (#1) | 14.50p (#2) | -0.20p |
| NZDUSD | Thu 13:30 UTC 14.00p (#1) | 13.40p (#3) | -0.60p |
| USDCAD | Fri 13:30 UTC 19.75p (#1) | 19.75p (#1) | 0.00p — SAME |
Mechanism: NFP fires 12x/year into Fri 13:30 UTC. Weekly jobless claims fires 52x/year into Thu 13:30 UTC — density ratio 4.3x. Per-release volatility is bigger on NFP, but the median-range calculation averages all 780+ weekly-claim cells against all 180+ NFP cells and the higher-density Thu slot wins on the median. Same mechanism as tue-1430-second-us-macro (2026-08-23): high-density weekly slots beat low-density monthly slots on median range. USDCAD is the exception because it inherits EXTRA NFP-day-specific USD-CAD flow that the other pairs don’t carry, tipping the balance back to Fri 13:30.
Novel finding: highest loudest/typical ratio of any family (1.95x)
USD-majors concentrate their loudness more tightly than any other family. Per-pair ratios: USDCAD 2.17x, USDCHF 2.11x, EURUSD 2.07x, GBPUSD 1.95x, USDJPY 1.89x, AUDUSD 1.73x, NZDUSD 1.73x. Family average 1.95x.
Contrast the earlier families: JPY-cross 1.62x, CHF-cross 1.80x, AUD-cross 1.62x, NZD-cross 1.58x, EUR-cross 1.79x, GBP-cross 1.78x. USD-majors are 8-24% tighter than every other family. Mechanism: every cross-pair dilutes the USD leg with a non-USD leg that responds to DIFFERENT domestic calendars — dispersing the loudness. USD-majors don’t. Every US-macro release lands full-strength on all 7 pairs simultaneously.
AUDUSD and NZDUSD sit at the low end (1.73x each) because they inherit Asia-morning quote-currency dilution from the AUD/NZD leg — RBA 03:30 UTC and RBNZ 02:00 UTC decisions leak small amounts of Asia-session volatility into the pairs’ median calculation.
Novel finding: zero Fed-decision cells in any pair’s top-20
FOMC fires 8x/year at Wed 18:00-19:00 UTC (the specific slot rotates by daylight-savings and briefly moved earlier during the 2019 Powell press-conference reshuffle). Across ~16 years of sample: ~128 FOMC releases into a single 30-minute cell. Weekly jobless claims: 52 × 16 = 832. Density ratio favors weekly by 6.5x, and the median-range calculation lands closer to the quiet-cell median for Wed 18:00 UTC. No FOMC cell survives into any pair’s top-20.
Same sparse-domestic-calendar-averaging mechanism as JPY-cross (03:00 UTC Tokyo lunch), CHF-cross (06:30 UTC CPI + 07:30 UTC SNB), AUD-cross (03:30 UTC RBA), NZD-cross (02:00 UTC RBNZ), GBP-cross (06:00 UTC UK CPI) — explained end-to-end in chfjpy-us-morning-loudest (2026-08-24). The domestic US macro calendar is concentrated in the same US-morning window as the release-frequent slots (NFP, claims, retail, PPI, ISM, JOLTS), so the FOMC slot doesn’t need a separate cell — it just piles more per-release variance onto Wed 18:00 UTC that gets diluted away by the ~700 quiet FOMC-free Wednesdays in between.
Seven-family arc summary
| Family | Date | In-window | Avg ratio | Notes |
|---|---|---|---|---|
| JPY | 2026-08-26 | 33/35 | 1.62x | 2 out (Wed 14:30, Tue 14:30 — still US-macro) |
| CHF | 2026-08-27 | 35/35 | 1.80x | cleanest, 0 domestic-CHF |
| AUD | 2026-08-28 | 33/35 | 1.62x | 2 out AUDNZD Sydney/Wellington |
| NZD | 2026-08-29 | 33/35 | 1.58x | 2 out AUDNZD (same pair) |
| EUR | 2026-08-30 | 34/35 | 1.79x | 1 out EURNZD Mon 14:30, Wed-dominant |
| GBP | 2026-08-31 | 35/35 | 1.78x | 0 Tuesdays, 6x 12:30 UTC |
| USD-major | 2026-09-01 | 35/35 | 1.95x | highest ratio, NFP #1 only for USDCAD |
| TOTAL | 7 families | 238/245 | 1.79x | 97.1% cross-family concentration |
Seven families × 35 top-5 cells = 245 slot-events sampled across the 7-day arc. 238 of 245 (97.1%) sit inside Tue-Fri 12:30-14:30 UTC. All 28 liquid FX pairs are now covered by at least one family (most by two, because e.g. GBPUSD is in both the GBP-cross family and the USD-major family). No 8th cross-family remains to run.
Verification note
Verified via 7 fresh /api/v1/calm-zones/scan pulls on 2026-09-01 (one per USD-major pair). Coverage window per pair: 2010-01-01 through 2026-08-08 approx (varies slightly by pair; typical n_days_total = 800-848 per weekday cell). Chart via one-off script reusing scripts/insights-charts/svg.ts + theme.ts primitives + sharp for rasterization; not committed under scripts/ (single-use, no future reuse expected). Closes the 7-day cross-family arc started 2026-08-26 with jpy-crosses. No 8th family exists — the 28 liquid FX pairs are exhausted.