Daylight saving shifts and the 2026 calendar
Posted: Tue Oct 27, 2026 7:10 am
Every spring and autumn, clocks change, and the market schedule slides relative to server time and to personal schedules.
The US and Europe don't shift on the same dates, so for a few weeks the gap between New York and London is one hour different from usual. In the US, clocks move on the second Sunday of March and the first Sunday of November. The European change comes on the last Sunday of March and the last Sunday of October. Australia and other southern hemisphere countries shift in the opposite direction on different dates.
Effects for scalpers: the London open lands an hour earlier or later in server time, the economic calendar times shift, and automated systems with fixed time filters break without any warning.
Checking every time-based rule around each change date is a small chore with a big payoff. Anchoring rules to UTC or to named sessions with a built-in daylight adjustment avoids the problem.
A friendly way to sanity check: set a calendar reminder two weeks before each clock change with the note "review time filters." On the day, a ten-minute check of every automated rule, alert and session definition prevents the strange week where everything is an hour off and nobody notices until results suffer.
Have time-based rules ever misfired around a clock change, and how are they handled now?
The US and Europe don't shift on the same dates, so for a few weeks the gap between New York and London is one hour different from usual. In the US, clocks move on the second Sunday of March and the first Sunday of November. The European change comes on the last Sunday of March and the last Sunday of October. Australia and other southern hemisphere countries shift in the opposite direction on different dates.
Effects for scalpers: the London open lands an hour earlier or later in server time, the economic calendar times shift, and automated systems with fixed time filters break without any warning.
Checking every time-based rule around each change date is a small chore with a big payoff. Anchoring rules to UTC or to named sessions with a built-in daylight adjustment avoids the problem.
A friendly way to sanity check: set a calendar reminder two weeks before each clock change with the note "review time filters." On the day, a ten-minute check of every automated rule, alert and session definition prevents the strange week where everything is an hour off and nobody notices until results suffer.
Have time-based rules ever misfired around a clock change, and how are they handled now?