Why exchange rates change all day in 2026: a 3-minute primer

Exchange rates change continuously during forex market hours (Sunday evening UTC through Friday afternoon UTC) because the global forex market trades 24 hours, with banks and institutions constantly updating bid/ask prices based on supply, demand, and news. Retail Japanese exchange shops typically update 1–3 times per day, so the rate you see at a shop may lag the live mid-market by hours.

TL;DR

• Forex trades 24/5 — Sunday evening through Friday afternoon UTC.
• Retail shops update 1–3 times daily — they're not real-time.
• The shop rate is essentially "morning's mid-market" + a spread — pre-built into the displayed number.
• Best time to exchange: late morning when shops have updated for the day.

How does the global forex market work?

Three things drive continuous price changes:

1. Supply and demand

Every minute, dozens of major banks make currency trades worth billions of dollars. Those trades shift the bid/ask prices that determine the mid-market rate.

2. News and economic data

Interest rate announcements (BOJ, Fed, ECB), GDP releases, unemployment numbers, geopolitical events — each causes immediate rate movements.

3. Carry trade and macro positioning

Hedge funds and institutions take long-term currency positions; their entry/exit moves the market.

The result: USD/JPY can move 0.3–1.5% in a single day, with some weeks seeing 3–5% movements.

How fast do retail shops update?

| Shop type | Update frequency | |---|---| | Wise / Revolut | Real-time at transaction | | Major Japanese ATM (7-Eleven Seven Bank) | Real-time via card network | | Dedicated Tokyo exchange shop | 1–3 times daily | | Small pawn-shop FX windows | Once daily (morning) | | Hotel front desks | Once daily or less |

The lag means: the rate you see at a small Tokyo shop in the afternoon may reflect the morning's mid-market, not the current afternoon's. If the rate has moved overnight or during the day, the shop rate may be slightly stale.

What causes the biggest USD/JPY moves?

• BOJ interest rate decisions (twice quarterly) — biggest single-event moves
• Fed rate decisions (every 6 weeks) — equally big
• Major geopolitical news (rare, but huge moves possible)
• Carry trade unwinds during global market stress

What this means for your trip

• ✅ Time exchanges in late morning when shops have updated.
• ✅ For real-time rates, use Wise/Revolut card transactions or 7-Eleven Seven Bank ATMs (network rate).
• ✅ Check the live mid-market before walking in — Yen Finder shows it.
• ⚠️ Don't try to time the market for a 1-week tourist trip — the daily moves are usually smaller than the spread cost.

Frequently asked questions

Are forex markets really 24/5?

Yes — Sunday evening (UTC) through Friday afternoon (UTC). Some specific exchanges have brief breaks but the global market is continuous.

Why don't shops update in real-time?

Operational cost. Real-time updates require automated systems; small shops post manually. Wise and Seven Bank ATMs have the infrastructure for real-time pricing.

When are forex rates most volatile?

• Around BOJ/Fed/ECB announcements (specific dates)
• During global financial market stress
• Within the first hour of European/US market open

Should I time my exchange to a specific market hour?

For a tourist trip, no — the daily move is usually 0.3–1.5%, small relative to the shop spread (1–3%). Optimize the shop, not the timing.

See also

• Article #1 — What is the mid-market rate?
• Article #9 — Best time of day to exchange
• Article #11 — Why bank's rate beats airport

Last verified 2026-05-07.