Trading Session
Also known as: forex sessions, London session, New York session, Asian session, market hours
What is it?
A trading session is one of the regional windows the 24-hour forex market divides into - Asian, London and New York - each defined by the hours its major financial centres are open and the currencies most actively traded during them. The market never closes between Sunday evening and Friday evening, but liquidity is far from evenly spread across it. In UTC terms the Asian session runs roughly 23:00 to 08:00, London 07:00 to 16:00 and New York 12:00 to 21:00.
- 23Asian session - 23:00 to 08:00 UTC Tokyo, Sydney and Hong Kong lead. EUR/USD often ranges around 20 pips across the whole window and spreads sit at their widest of the day. Yen and Australian dollar pairs are the active ones.
- 07London session - 07:00 to 16:00 UTC The largest FX centre opens and volume steps up sharply. Spreads tighten, European data lands, and the day's directional move frequently begins here.
- 12London-New York overlap - 12:00 to 16:00 UTC Both centres trade at once. This is the deepest liquidity and the tightest spread of the day, and where the largest ranges on EUR/USD and GBP/USD occur.
- 16New York afternoon - 16:00 to 21:00 UTC London closes and volume falls away. Moves made during the overlap often stall or retrace, and the daily rollover near 21:00 widens spreads and applies swap.
The four hours where London and New York overlap, about 12:00 to 16:00 UTC, carry the heaviest volume of the day: spreads are at their tightest, order books are deepest, and the largest directional moves on EUR/USD and GBP/USD usually happen there. Session choice therefore changes what a strategy actually meets. A breakout system run through the Asian range, where EUR/USD often travels 20 pips in nine hours, is stopped out by noise it never saw in a backtest weighted toward the overlap.
A mean-reversion system has the opposite problem during the overlap. This is why most bots ship with a session filter: the same rules produce different results at different hours, and restricting them to the right window is often a larger improvement than changing the rules.
Why it matters: Liquidity, spread and typical range differ several-fold across the Asian, London and New York sessions, so the hour a strategy trades changes its results.
Session hours set the spread and the range a strategy meets, so an unfiltered bot trades the same rules in conditions they were never measured in.
Real-world example
EUR/USD commonly ranges about 20 pips through the Asian session and 60 or more during the London-New York overlap, so an identical 25-pip stop is noise in one window and meaningful structure in the other.
How SignalBots handles it
SignalBots timestamps every signal in UTC, so you can see which session it was generated in and judge whether the setup fits the liquidity you will actually be trading into. See /risk-warning.
Pro tip
Compare your strategy's results session by session before you change a single rule. A losing system is often a profitable one running three-quarters of its trades in the wrong window.
Common pitfalls
Setting a session filter in broker server time and assuming it is UTC. Most MetaTrader servers run two or three hours ahead, which silently shifts the whole window.
Frequently asked questions
Which session is best to trade?
The one that matches your strategy. The London-New York overlap offers the tightest spreads and the largest moves, which suits breakout and momentum systems, while the Asian range suits mean-reversion approaches that need price to stay contained.
Do session times shift with daylight saving?
Yes, and asymmetrically. London and New York change on different dates, so the overlap window moves by an hour twice a year. Anchor your filter to UTC and adjust the offsets rather than hard-coding local hours.
What is the Asian session known for?
Narrow ranges on the European and dollar majors, and far more activity on yen and Australian dollar pairs, where Tokyo and Sydney are the natural centres. Spreads on EUR/USD are usually at their widest of the day.
Should a bot trade through the daily rollover?
Rarely. Liquidity thins at the rollover, spreads widen sharply and swap is applied to open positions. Most session filters exclude a window around it for exactly that reason.
Is the weekend gap a session issue?
It is a related one. The market closes Friday evening and reopens Sunday, and price can open away from Friday's close. A position held across it is exposed to a move no stop can prevent. Your capital is at risk.
Trading involves substantial risk of loss. Historical and backtested results do not guarantee future performance. Read the full risk warning.
