When the Clocks Change: A Method for Re-Mapping the FX Day Across Two Transition Weeks

Key takeaways

1. The UK and the EU leave summer time on Sunday 25 October, while the United States and most of Canada follow on Sunday 1 November (GOV.UK; timeanddate).

2. From Monday 26 October, UK data and the London open move one hour later in UTC, while US data stay at 12:30 UTC until 1 November and then move to 13:30 UTC.

3. Re-map your calendar in UTC before each change and pay most attention to the in-between week, when the usual gaps between sessions are different.

The development

This weekend begins the autumn clock change. In the UK, clocks go back at 02:00 on Sunday 25 October, from British Summer Time to Greenwich Mean Time (GOV.UK). Most of Europe changes on the same night, from 03:00 central European summer time to 02:00 standard time. The United States and the parts of Canada that still change their clocks follow a week later, on Sunday 1 November (timeanddate). Japan does not use daylight saving time, so Tokyo hours in UTC do not change.

The change comes before a busy week: the UK Budget on Wednesday 28 October (HM Treasury), the Federal Open Market Committee meeting on 27–28 October (Federal Reserve), the ECB press conference from 13:45 to 14:45 UTC on 29 October (ECB), and the Bank of Japan meeting on 29–30 October.

Market transmission

Activity in FX follows local working hours, not UTC. When London moves its clocks, the London morning moves one hour later in UTC. This has four practical effects for the week of 26 October:

• UK data. Releases due at 07:00 London time arrive at 07:00 UTC rather than 06:00 UTC, as with UK retail sales, released at 06:00 UTC today.

• Tokyo–London handover. London's morning starts one hour later relative to Tokyo, so the overlap that matters for GBPJPY and other yen crosses is shorter.

• The London fix. The WM/Reuters 4 p.m. benchmark is calculated from 15:57:30 to 16:02:30 London time (LSEG). In UTC it moves from about 15:00 to about 16:00.

• The London–New York overlap. Because the US has not yet changed, the overlap is about one hour longer than usual for a single week, and US data at 12:30 UTC arrive earlier in the London afternoon than normal.

From 2 November, US releases due at 08:30 New York time arrive at 13:30 UTC.

What to monitor next

• Your own alerts, platform session filters and any orders tied to sessions, which may use local time.

• The 26 October to 30 October week, when European and US offsets differ from normal.

• Liquidity in the first hour after the London open, which now starts later relative to Asia.

• Release times for the FOMC statement, ECB decision and UK Budget, stated in UTC.

Reusable lesson

A repeatable method works in four steps. First, list every recurring event you rely on, such as data releases, the open and close of your main sessions, benchmark fixes and option cuts. Second, write each one in local time with its time zone. Third, convert each to UTC for the transition week and again for the week after. Fourth, flag every item whose UTC time changes and adjust alerts and any automated rules. Use the same check in March, when the order reverses and the US changes first.

Invalidation and risk

The main risk is human error: an alert that fires an hour early, a stop-loss order placed for a session that has moved, or a release that seems "late" when it is on time. Calendars and platforms do not always update together, so check against the official source of each release. Canada's rules are changing province by province, so treat Canadian local times with care (timeanddate). If US legislation on permanent daylight time were enacted, future schedules would change, but it has not become law.

Glossary

Benchmark fix: A published reference exchange rate calculated over a short window, used to value portfolios and settle many transactions.

Session overlap: The hours when two major trading centres are open at the same time, usually the most liquid part of the day.

Option cut: The fixed time of day at which FX options expire, which can concentrate hedging flows.

Sources

GOV.UK (2026-10-23): When do the clocks change?

timeanddate.com (2026-10-02): DST ends in the US and Canada 2026; Europe ends DST 2026

LSEG (FTSE Russell) (2026-10-23): WMR FX Benchmarks Methodology

Federal Reserve (2026-10-23): Meeting calendars and information, 2026 FOMC meetings

European Central Bank (2026-10-23): Downlink parameters for TV stations, 29 October 2026

HM Treasury (GOV.UK) (2026-07-31): Chancellor letter to the Treasury Select Committee - Budget 2026 date

Disclaimer

This note is provided by the SummitFx Project for general education and market context only. It is not investment advice, not a solicitation to buy or sell any instrument, and not a personal recommendation. Foreign exchange and related markets are leveraged and can result in the loss of some or all of your capital. Figures are believed accurate at the time of research and may already be stale. Always verify live prices, official releases, and your own risk limits before acting. Past market behaviour does not determine future results.