PSH: Previous Session High and Low
Also known as: PSH, PSL, session high and low, Asian range high and low, London high and low
What is it?
The previous session high and low are the extremes of the trading session that just ended - most often the Asian range, read at the London open, or the London range, read at the New York open. They serve the same purpose as yesterday's extremes but on a much shorter clock, which makes them the reference intraday traders actually work from. The Asian session is typically quiet and narrow, so it leaves a compact range with orders stacked on both sides; London then opens and very often runs one side of it before establishing the day's direction.
If Asia ranged between 1.0838 and 1.0861 on EUR/USD, a London open that pushes to 1.0866 and reverses has swept the session high and given the day its first real signal. The advantage over the previous day high and low is freshness. A session that ended two hours ago reflects current positioning, while yesterday's extremes may belong to a market that has already moved on.
The disadvantage is that session ranges are narrower, so sweeps are smaller and easier to mistake for ordinary noise.
Why it matters: The last session's extremes are the freshest intraday liquidity levels, and the next session's opening move very often runs one of them first.
The first hour of a session frequently resolves against these levels, so they decide where the day's opening move is likely to start and stall.
Real-world example
EUR/USD ranged 1.0838-1.0861 through Asia. London opened, ran to 1.0866, reversed, and traded down to 1.0812 - the session high was swept before the real move began.
How SignalBots handles it
SignalBots tags every signal with the session it fired in, so a London-open entry is not read as if it happened in thin Asian liquidity. See /risk-warning.
Pro tip
Mark the Asian range before London opens and watch which side goes first - the swept side often points away from where the day actually travels.
Common pitfalls
Treating a narrow Asian range as a breakout setup. The first move out of it is more often a raid on the orders sitting just beyond than the start of a trend.
Frequently asked questions
Which session should I mark?
The one immediately before the session you trade. If you trade London, mark the Asian range; if you trade New York, mark the London range. Marking all of them at once clutters the chart without adding information.
How is this different from the previous day high and low?
Timescale and freshness. Session extremes are hours old and reflect current positioning; the previous day extremes are up to a day old and carry more accumulated attention. Both attract orders, but session levels move the market first.
What are the standard session hours?
In UTC terms, Asia runs roughly 00:00 to 08:00, London 08:00 to 16:00, and New York 13:00 to 21:00, with a London and New York overlap that carries most of the day's volume. Exact boundaries vary by convention and by daylight saving.
Does a narrow session range mean a big move is coming?
It often precedes expansion, because a compressed range concentrates orders on both sides. It does not tell you the direction, so trading it as a breakout in either direction puts capital at risk on a coin flip.
Do these levels work on crypto?
Less cleanly. Crypto has no session close, so the ranges are conventions rather than genuine boundaries. They still mark where orders cluster, but the effect is weaker than in forex.
Trading involves substantial risk of loss. Historical and backtested results do not guarantee future performance. Read the full risk warning.
