A market open 24 hours a day sounds like it removes timing from the equation. It does the opposite. The same pair can be nearly motionless at one hour and cover its entire daily range in the next, with no headline responsible — only the clock.
Four sessions, one continuous market
Forex has no open or close, but banks do. As each financial centre starts its working day, liquidity in the currencies it deals in thickens. The result is four overlapping sessions, quoted here in UTC because local clocks shift with daylight saving and UTC does not:
- Sydney — roughly 21:00 to 06:00. The week begins here.
- Tokyo — roughly 00:00 to 09:00. Asian liquidity, JPY, AUD and NZD activity.
- London — roughly 07:00 to 16:00. The largest single session by volume.
- New York — roughly 12:00 to 21:00. US data lands here.
London matters more than its share of hours suggests. A disproportionate slice of global currency turnover is dealt through London, so the European morning is when most pairs get their first genuine directional push of the day.
The overlap that matters
From about 12:00 to 16:00 UTC, London and New York are both open. Two of the deepest liquidity pools are live simultaneously, and that four-hour window routinely carries the heaviest volume, the tightest spreads and the widest ranges of the day.
It is also when most US economic data is released. A figure that prints during the overlap meets a market with maximum participation; the same figure at 22:00 UTC would move price further on far less volume, because there is less depth to absorb it.
The practical consequence for a new trader is simple. If you can only trade for a few hours, trading during the overlap gives you the tightest costs and the most genuine movement. Trading at 03:00 UTC on EUR/USD means paying a wider spread for a market that is mostly drifting.
Pairs have preferred hours
Liquidity is currency-specific, not global. A pair is most active when at least one of its two currencies is in its home session.
- EUR/USD, GBP/USD — London and the overlap.
- USD/JPY, AUD/JPY — Tokyo, and again on US data.
- AUD/USD, NZD/USD — Sydney and Tokyo.
This is why a strategy can appear to stop working when nothing about it changed. A breakout method tuned to the London open produces very different results applied to the Asian session, where ranges are narrower and false breaks more common.
The edges of the week
Two moments deserve caution.
The Monday open. Prices resume from where they stopped on Friday, but the world kept happening over the weekend. If something significant occurred, price can gap — open at a different level entirely, skipping the prices in between. A stop loss sitting inside that gap does not get filled at your level; it gets filled at the first available price on the other side.
The Friday close. Liquidity thins into the weekend as desks square up. Spreads widen, moves get erratic, and any position you hold carries weekend gap risk until Monday.
Rollover — the daily swap charge or credit for holding a position overnight — is applied around 21:00 UTC, and triples on Wednesday to account for the weekend. Spreads often widen briefly at that moment on thin books.
What to take from this
- Four sessions — Sydney, Tokyo, London, New York — run continuously on weekdays.
- The London–New York overlap (about 12:00–16:00 UTC) is the deepest and cheapest window.
- A pair is liveliest when one of its currencies is in its home session.
- Strategies are session-dependent; the same rules give different results at different hours.
- Weekend gaps can jump a stop. Size accordingly if you hold into Friday's close.
Next: who is actually trading in these sessions, and why most of that volume has nothing to do with speculation.