A scalper's "safe hours" rule broke for a few weeks every March
Posted: Sat Oct 31, 2026 11:11 am
A trader in central Europe built a simple rule: no new entries between 22:45 and 23:15 local time, because that is when the spread on the majors blows out around the New York close. The rule worked for months. Then one week in March, the stop-outs started showing up at 22:00 local time instead, always on quiet candles, always on the ask side.
The first suspicion was the broker. Then a data problem. The actual cause was the calendar. The US moves its clocks forward on the second Sunday of March, while Europe waits until the last Sunday. For roughly two to three weeks, New York is on daylight time and Europe is not, so the gap between them shrinks from six hours to five. The 5pm New York rollover, anchored to New York, landed an hour earlier on the European clock. The local clock rule was one hour off and nothing on the screen had hinted at it.
Now the twist. The platform's server time did not seem to move at all. For brokers whose server clock follows the New York close, the rollover stays at server midnight all year, because the server clock shifts with US rules. The trader had been filtering on a clock, the local one, that drifts against the thing being avoided, while the server clock, which tracks it, was sitting right there in the Market Watch window the whole time.
The same mismatch returns in autumn for about a week, between the European clock change and the US one. It also moves the London open relative to New York, which shifts overlaps, news timing and volatility windows by an hour.
Server clocks vary though. Some brokers use fixed offsets that never follow daylight saving at all, so the first step is finding out what a specific broker does and testing it against a logged spread spike.
For anyone using time-based filters, how do you keep them aligned during the weeks when US and European clock changes do not match?
The first suspicion was the broker. Then a data problem. The actual cause was the calendar. The US moves its clocks forward on the second Sunday of March, while Europe waits until the last Sunday. For roughly two to three weeks, New York is on daylight time and Europe is not, so the gap between them shrinks from six hours to five. The 5pm New York rollover, anchored to New York, landed an hour earlier on the European clock. The local clock rule was one hour off and nothing on the screen had hinted at it.
Now the twist. The platform's server time did not seem to move at all. For brokers whose server clock follows the New York close, the rollover stays at server midnight all year, because the server clock shifts with US rules. The trader had been filtering on a clock, the local one, that drifts against the thing being avoided, while the server clock, which tracks it, was sitting right there in the Market Watch window the whole time.
The same mismatch returns in autumn for about a week, between the European clock change and the US one. It also moves the London open relative to New York, which shifts overlaps, news timing and volatility windows by an hour.
Server clocks vary though. Some brokers use fixed offsets that never follow daylight saving at all, so the first step is finding out what a specific broker does and testing it against a logged spread spike.
For anyone using time-based filters, how do you keep them aligned during the weeks when US and European clock changes do not match?