Sessions and killzones: when to trade and how to measure it

In forex the when matters almost as much as the what. The same setups have very different results at 3 in the morning and at 3 in the afternoon, because liquidity, spread, volatility and participants change. The ICT approach popularised the idea of killzones: time windows in which setups are sought. Let's see what they are, how to translate them correctly to your time zone and, most importantly, how to measure whether they work.

Why time matters: liquidity and participants

The market passes the baton between financial centres. Volatility isn't uniform: it concentrates at the London and New York opens, and especially in the hour around the release of macroeconomic data. Concrete effects:

• Lower spreads in moments of high liquidity, higher at night and at rollover.
• Wider and more persistent directional moves during London and New York.
• Aimless moves at dead hours: price oscillates going nowhere and stops out positions.

The killzones (New York time, ET)

The values below are indicative and widespread in the ICT community; they aren't a law and must be verified on your own data.

Translating to UK and Italian times without mistakes

The most frequent error is converting badly with daylight saving. Rules:

• New York is on ET: UTC−5 in winter (EST), UTC−4 in summer (EDT).
• The UK (GMT/BST) is UTC+0 in winter, UTC+1 in summer; Italy (CET/CEST) is UTC+1 in winter, UTC+2 in summer.
• When the US and Europe are both on daylight saving or both on standard time, the difference between New York and the UK is 5 hours; with Italy it's 6 hours.

Practical tip: set the chart to UTC or New York and always work in the same time zone; convert only to know when to sit in front of the screen.

Building the Asian range

Many intraday models start from the Asian range: the high and low formed during the Asian session. Define it in writing:

Asian range = [low, high] of the candles between 00:00 and 06:00 UTC (parameters to fix)
Valid if: range amplitude < 1.0 x daily ATR(14)   ("compressed" day)
Useful levels: Asian high (AH), Asian low (AL), midpoint of the range

The Asian range is useful for two reasons: it defines obvious liquidity levels (high and low) that London can "take" and gives an idea of the compression before expansion. Some traders consider days with a narrow Asian range more reliable.

Session and pair

Not all pairs move at the same hours. General rule: trade pairs when the currencies involved have their session.

The economic calendar inside the killzones

Many windows contain high-impact announcements (US inflation at 8:30 ET, for example). Before trading check the economic calendar: if important news is expected in a killzone, decide in advance whether to stay out, reduce size or trade only after the initial reaction. Don't add positions straddling the announcement.

How to check whether a time slot has an edge

Killzones are a hypothesis. Here's a simple, honest test, on 6 months of data:

1. Split the day into one-hour slots (in UTC).
2. For each slot calculate: average size of moves (in ATR or pips), average spread and, if you have an entry rule, expectancy in R.
3. Build a table and a bar chart.
4. Observe: are volatility and your strategy's result really concentrated in the killzones? Do they change between summer and winter?

A single session: the advantage of limiting yourself

Deciding to trade only one killzone (for example 07:00-10:00 UK time) has advantages beyond statistics: fewer hours in front of the screen, less overtrading, a steadier routine and better emotional control. For a working trader, it's often the only sustainable choice.

Common mistakes

• Converting daylight saving badly and testing the wrong hour.
• Trading all hours hoping not to miss opportunities.
• Ignoring announcements inside the killzone.
• Believing in killzones without verifying them on your own data.
• Comparing summer and winter days without accounting for the hours.

In short

• Liquidity and spreads vary with the hour: the London and New York sessions are the most active.
• The killzones (Asia, London, New York, London close) are indicative: convert them carefully accounting for daylight saving.
• Always work in a fixed time zone (UTC or ET) and define the Asian range in writing.
• Verify with your data in which slots volatility and your strategy pay most.
• Limiting yourself to one killzone improves discipline and emotional control.

Practical exercise

1. Set the chart to UTC and define the Asian range in writing.
2. Over 6 months calculate the average ATR per time slot and build the table.
3. Choose one killzone and stay in it for 30 days: how many valid setups appear per day?