The foreign exchange market runs around the clock from Sunday evening to Friday evening New York time, so it can feel as if clocks do not matter. They do. The market itself does not shift, but the hours at which each financial centre is open do, and those hours decide when liquidity is deep and when it is thin. If you trade by the clock on your wall, you need to know when that map changes.
Different places change on different dates
The key detail is that daylight saving time (DST) does not start and end everywhere on the same day. In 2026 the European Union and the UK end summer time on the last Sunday of October, which is today, 25 October. The United States and Canada end DST a week later, on 1 November. Japan, China and most of Asia do not observe DST at all, and Australia and New Zealand move in the opposite direction, because their summer begins in the northern autumn.
This produces an awkward two-week window each autumn and spring in which the London and New York overlap is one hour shorter or longer than usual when measured in your local time. For the week between 25 October and 1 November, London opens an hour later relative to New York than it did last week, so the overlap between the two is compressed by an hour on your screen.
What actually moves
Think of each session as anchored to local business hours, not to a fixed UTC time. A bank dealing desk in London opens around 08:00 London time whether that is 07:00 or 08:00 UTC. So when London returns to standard time, its open arrives an hour later in UTC terms. Tokyo, which never changes, does not move at all, so the Tokyo–London handover shifts relative to it.
| Centre | Typical local business hours | DST status |
|---|---|---|
| Sydney | 08:00–17:00 | Moves in the opposite season |
| Tokyo | 09:00–18:00 | No DST |
| London | 08:00–17:00 | Ends 25 Oct 2026 |
| New York | 08:00–17:00 | Ends 1 Nov 2026 |
The table is illustrative of local hours; exact desk hours vary by firm. The point is the relationship: only the DST observers move relative to each other.
The things that quietly break
Most of the damage from clock changes comes from tools and habits that assume a fixed offset:
- Alerts and calendars. An economic calendar set to a fixed UTC offset will show releases an hour off after a change. Check that your calendar is set to a named time zone (such as America/Toronto) rather than a raw offset.
- Chart session markers. Indicators that shade sessions by fixed server-time hours will be wrong for the affected weeks.
- Broker server time. Many brokers run server time that follows New York closes and shifts with US DST. Daily candles then close at a different clock time, which changes what a “daily high” or “daily close” means on your chart. A level you drew last week may not line up with this week’s daily candle boundaries.
- Scheduled releases. Data agencies publish at local times. A US release at 08:30 Eastern is the same Eastern time all year but lands at a different UTC time before and after 1 November.
- Your own routine. If your strategy depends on the first hour after the London open, that hour is now at a different time for you.
Why the overlap matters
As discussed in our guide to forex trading sessions, the London–New York overlap is typically when volume and tick activity are highest, because the two largest dealing centres are active together. Spreads are usually tightest then, and breakouts have more participation. When the overlap is cut down by a clock change, there is simply a different window in which that liquidity is available to you, and your usual entry times may fall in a quieter stretch. See also spreads and slippage for why quieter periods cost more to trade in.
A practical checklist for the transition weeks
- Write down, in your own local time, when London and New York open this week and next week. Do not rely on memory.
- Confirm your economic calendar’s time zone setting and compare one known release against an official source.
- Check your broker’s server time against UTC and note when its offset changes.
- Re-check any automated alerts, scripts or expert advisors that use hard-coded hours.
- Consider trading smaller or not at all in your first session after a change until you have confirmed that everything lines up. A mistimed entry caused by a clock error is the most avoidable kind of loss.
Do not over-read it
A one-hour shift does not change the nature of the market, and it does not create an edge on its own. Some traders look for patterns around DST changes, but any such pattern would need honest testing, as described in backtesting honestly, and many would be too small to survive trading costs. The sensible position is a modest one: DST changes your logistics, not the market’s fundamentals.
The simplest habit is to keep your trading plan in a named time zone and to re-verify it twice a year. Put a reminder in your calendar for the last Sunday of March and October, and for the second Sunday of March and first Sunday of November in North America. It costs five minutes and removes a whole class of avoidable errors.
This article is general education, not trading advice. Examples are illustrative.