When the clocks change: forex session times in the gap weeks (UK)
Twice a year the UK and the US change their clocks, but not on the same weekend. For the weeks in between, New York is four hours behind London instead of five, and everything driven by New York happens an hour earlier in UK time: the New York kill zone, US data, the stock market open, the daily rollover and the weekly open. If you trade the New York session from the UK, these are the weeks to watch.
The dates
| Gap | US changes | UK changes | Weeks affected |
|---|---|---|---|
| Autumn 2026 | Sun 1 Nov 2026 (clocks back) | Sun 25 Oct 2026 (clocks back) | 26 to 30 October 2026 |
| Spring 2027 | Sun 14 Mar 2027 (clocks forward) | Sun 28 Mar 2027 (clocks forward) | 15 to 26 March 2027 |
| Autumn 2027 | Sun 7 Nov 2027 | Sun 31 Oct 2027 | 1 to 5 November 2027 |
The rule: the US changes on the second Sunday of March and the first Sunday of November; the UK on the last Sunday of March and the last Sunday of October.
What moves, and what doesn’t
| Event | Normal (UK time) | Gap weeks (UK time) |
|---|---|---|
| Asian range | 00:00 – 06:00 | 00:00 – 06:00 (no change) |
| London kill zone | 07:00 – 10:00 | 07:00 – 10:00 (no change) |
| London open / close | 08:00 / 17:00 | 08:00 / 17:00 (no change) |
| New York midnight open | 05:00 | 04:00 |
| New York kill zone | 12:00 – 15:00 | 11:00 – 14:00 |
| US data (NFP, CPI) | 13:30 | 12:30 |
| US stock market open | 14:30 | 13:30 |
| Daily rollover / forex week open | 22:00 | 21:00 |
Why it catches traders out
- Data comes early. Sitting down at 13:15 for a 13:30 number, only to find it came out 45 minutes ago, is a classic gap-week mistake.
- Your indicator is an hour out. Most session indicators use a fixed offset from the broker’s server clock. In the gap weeks their New York box sits an hour late.
- Your broker’s chart shifts too. Most brokers run their server clock at New York + 7, so it changes on the US dates, not the UK ones. The chart’s daily candle and your UK clock drift apart for those weeks.
- Spreads widen earlier. The daily rollover, when spreads blow out, comes at 21:00 UK instead of 22:00. A stop that’s fine at 21:30 normally can get hit by a spread spike.
How to stop it costing you
Check the live market hours clock, which shows a warning in the gap weeks, and put an indicator on your chart that knows both calendars. The free TTL Kill Zone Clock follows the UK, US and Australian clock changes on their own dates, reads your broker’s server offset, and adds a gap-week note to its panel so you can’t miss it.
A kill zone indicator that gets the gap weeks right
The TTL Kill Zone Clock draws the Asian range, the London and New York kill zones in UK time, yesterday’s and last week’s highs and lows, with a live UK session clock and sweep alerts. Free for MT4 and MT5, and it handles the clock changes by itself.
Download the Kill Zone Clock freeMore on the sessions themselves: forex market hours in UK time and New York session times in UK time.
Frequently asked questions
Do forex market hours change when the clocks go back?
In UK time, yes for anything driven by New York. In the gap weeks between the UK and US clock changes, the New York kill zone, US data, the US stock open and the daily rollover all happen an hour earlier in UK time. London times don’t change.
What time does the New York session open in the UK when the clocks change?
Normally the New York kill zone is 12:00 to 15:00 UK and US data lands at 13:30. In the gap weeks it’s 11:00 to 14:00 and data lands at 12:30.
When do the US clocks change?
On the second Sunday of March (forward) and the first Sunday of November (back). The UK changes on the last Sunday of March and the last Sunday of October.
What time does forex open on Sunday in the UK?
22:00 UK time on Sunday most of the year, and 21:00 in the gap weeks. It follows 17:00 New York time.
Educational content only, not financial advice. Trading carries a high level of risk and you can lose more than you expect. Examples use illustrative prices.