Direct answer
There is no single universal “London session start time on MT4” that applies to everyone, because the exact clock time depends on what timezone your MT4 chart is using and what server-time setting your broker provides. In practice, the London session start is tied to the London trading hours being displayed in your platform’s time reference, not to a fixed global hour.
How it works in MT4
MT4 charts show timestamps, but MT4 does not inherently know a trader’s preferred “session definition.” Instead, you typically see session timing in one of these ways:
- Chart time reference: Your broker’s server time and the chart’s timezone setting determine what the displayed clock time means.
- Session definitions used by indicators/tools: Some session-related indicators mark the London window using rules (often based on a named market timezone) and then convert that window into your chart time.
So when someone asks, “what time does the forex London session start on MT4?”, the real question is usually: what hour does the London trading window begin after it is converted into your MT4 chart time?
Example checks (no guesswork)
Use these checks to determine the start time on your own MT4 installation:
- Confirm broker server time vs your chart display. Compare the time shown on the chart with the broker/server time your platform provides.
- Identify the timezone basis of any session tool you use. If you use an indicator that highlights sessions, it usually assumes a specific market timezone and converts it to your chart.
- Account for daylight saving time differences. The London region and other regions used for conversion can change their clocks at different dates, so the same “session start” can appear to shift by an hour on your chart across the year.
A useful verification method is to select a day when London trading is clearly active, then check the first chart hour that your session marker begins and record that as your platform-specific “start.”
Relevant limitations and risks
Even with verification, be cautious:
- No universal start time exists across all MT4 setups. Different brokers and chart settings can show different clock times.
- Session windows can be defined differently. Some definitions use a start hour and end hour, others use broader ranges.
- Your own setup matters. If your server time or indicator settings change, the displayed start time can change too.
If you need one number, the safest approach is to derive it from your own MT4 timezone and session-definition settings rather than relying on a copied “London start time” from another source.