Forex liquidity through the day — when the spread is tightest

A trader I know once told me he lost money on EUR/JPY at half past three in the morning, "because I couldn't sleep and the chart looked clean". The spread, which had been 1.2 pip at midday, had widened to nearly five. His order filled with slippage, and the stop loss was taken out by a move that London-hour liquidity would have absorbed without a flicker. He had the direction right; he was simply wrong about the hour. That is the heart of this article: forex liquidity changes by an order of magnitude across the day, and the hour you choose often matters more than the direction.

What forex liquidity actually means

Liquidity is the market's capacity to absorb your order without visibly moving the price. When the market is deep, buying one standard lot of EUR/USD shifts the rate by a fraction of a pip, and the gap between the best bid and the best offer — the spread — is minimal. When the market is thin, the reverse happens: the spread widens, every sizeable order pushes the price, and slippage can swallow the entire risk plan.

Global daily turnover in the foreign-exchange market is around 7.5 trillion USD, according to the Triennial Central Bank Survey from the Bank for International Settlements (BIS, 2022). But that figure, averaged across the full day, hides the most important fact: the money does not flow evenly. Most turnover concentrates in a handful of European and American hours, and between them the order book thins and the cost of entry rises. Every time in this article is given in Central European Time (CET) — the time on the clock in Warsaw or Frankfurt.

The Asian session — calm, but more expensive

The Asian session, roughly from midnight to nine in the morning CET, is the quietest of the day. The dominant centre is Tokyo and the dominant currency is the Japanese yen. Yen pairs (USD/JPY, EUR/JPY, GBP/JPY) trade with respectable liquidity in these hours, because that is when Japanese banks, exporters settling contracts and the Bank of Japan are all active. The major non-yen pairs, such as EUR/USD or GBP/USD, are watched in this window rather than traded.

The consequence shows up directly in the spread. EUR/USD, which costs 0.2–0.3 pip during the most liquid hours, typically widens to 0.8–1.2 pip in the Asian session. For someone scalping short moves at a one-to-one reward-to-risk, that is an extra cost of several to a dozen percent on every trade — a cost that has nothing to do with how good the analysis was.

The London session — the deepest book of the day

London is the largest FX centre in the world. The BIS Triennial Survey 2022 found that around 38 percent of global FX turnover passes through desks located in the United Kingdom — more than through any other place on the map. The session opens around eight to nine in the morning CET and runs until roughly six in the evening. These are the hours when the order book is deepest, the spread on the major pairs is tightest and technical opportunities are most plentiful.

The first hours of the London open are especially lively for sterling pairs — GBP/USD can generate dozens of pips of range in that window before New York wakes up. This is why many day traders who focus on the pound confine their session to the morning.

"The best time to trade is when the markets overlap. That is when liquidity is at its highest and the moves are at their cleanest." — Kathy Lien, *Day Trading and Swing Trading the Currency Market*, Wiley, 2016.

The London–New York overlap — the daily optimum

The single most important window of the day is the overlap between the London and New York sessions, roughly from two to five in the afternoon CET. In those few hours, dealers from London, Frankfurt, Paris, New York and Chicago are all at their desks at once. Most institutional capital is active simultaneously, and on top of that this is exactly when the key macro prints for the dollar land — Non-Farm Payrolls, the Consumer Price Index (CPI) and decisions from the Federal Open Market Committee (FOMC).

The result is that the EUR/USD spread compresses to 0.2–0.3 pip at ECN brokers, and sizeable retail orders fill with virtually no slippage. If you only trade once a day and would rather not fight the market for every pip of cost, this window gives you the most for the least. The second valuable overlap is the short, roughly one-hour Tokyo–London handover in the morning, useful mainly for yen pairs — I have unpacked it in a separate piece on the Tokyo–London overlap.

Rollover — the hour when the spread can blow out

There is a moment beginners rarely hear about that can catch them off guard: the daily rollover. At most brokers it falls around eleven at night to midnight CET, because that is when midnight on the broker's server time (usually New York) occurs. It is the accounting end of the trading day — the moment swap points are charged and banks square their books.

The practical effect is that for those few minutes liquidity can evaporate. Banks pull their quotes, the book thins out, and the EUR/USD spread — which is 0.25 pip in the optimal window — can briefly run several times wider. Worse, this coincides with the end of the New York session and the quiet stretch before Tokyo opens. A market order placed at exactly that moment can fill with slippage you would never see at any other hour. If your strategy does not require you to be present then, simply avoid it.

Real spread differences on EUR/USD

EUR/USD is the most actively traded pair in the world and the best reference point for measuring liquidity over time. The table below shows how the spread on an ECN account typically changes across the day — an averaged picture, not a promise, since exact values depend on the broker, but the proportions are repeatable.

The difference between 0.25 pip in the overlap and 2 pips at rollover is a factor of eight. For someone running a dozen trades a day on a standard lot, that gap turns into hundreds of dollars a month in costs alone — money handed over not because the analysis was wrong, but because the hour was. For more on the mechanism behind these window-by-window differences, see the overview of the best hours to trade forex.

What to do tomorrow

1. Check your broker's spreads at three different hours. Open the historical EUR/USD quotes in your platform and compare the spread at three in the morning, at eleven and at three in the afternoon CET. If the widest is more than five times the narrowest, your broker uses session-dependent variable spreads — and you have just seen what trading outside the main hours really costs.
2. Mark two to five in the afternoon as your default entry window. If you trade the majors and have no reason to sit at the chart around the clock, plan your decisions for the London–New York overlap. These are the hours when the spread is tightest and slippage is smallest.
3. Flag eleven at night as a no-new-positions zone. Note above your monitor that the rollover window (roughly 23:00–00:00 CET) is when the spread can widen several times over. If you are holding a position then, check that your stop loss is not set too tightly relative to normal noise.
4. Match the pair to the hour, not the other way round. Before you click, ask yourself one question: is the local centre for this currency actually open? Trade yen pairs while Tokyo is alive, sterling pairs at the London open, and exotics only during the local hours of their own banks.

Related reading: the London session — the deepest book in the world and the core of European trading; the New York session — the hours when US macro data moves the market.