When does the clock change for daylight saving time (and back)?
Overview of time changes in Europe and the US, with automatically calculated dates for the coming year. How Masterclock NTP clocks handle the transition automatically.
For ordinary clocks that is manual fiddling. An NTP- or GPS-controlled clock does it fully automatically: it knows the rules of your time zone and moves itself at the right moment, without anyone having to intervene. That way all the clocks in a building always show the correct time together, even on the two changeover nights.
Twice a year, clocks are adjusted in most European countries and in large parts of North America. For organisations with many clocks, displays and IT networks, each transition brings maintenance time and costs.
Next time change
The counter below is automatically calculated each year.
Europe: last Sunday of March and October
In the European Union and the European Economic Area, clocks are adjusted twice a year:
- Winter time to summer time (spring): on the last Sunday of March, clocks move forward one hour at 02:00 to 03:00. The night is one hour shorter.
- Summer time to winter time (autumn): on the last Sunday of October, clocks move back one hour at 03:00 to 02:00. The night is one hour longer.
United States and Canada
Different dates apply in the US and Canada:
- Spring forward: on the second Sunday of March, clocks move forward one hour at 02:00.
- Fall back: on the first Sunday of November, clocks move back one hour at 02:00.
What costs does the clock change involve?
If your organisation has clocks in hard-to-reach locations (production floors, warehouses, operating theatres, studios, factory halls), each manual adjustment costs:
- Labour time: technicians who must physically visit each clock
- Downtime: clocks temporarily showing the wrong time
- Compliance risk: log files and audit trails with inconsistent timestamps
How does Masterclock eliminate this problem?
Masterclock NTP time servers (such as the NTP100 and GMR6000) synchronise all your clocks automatically via GPS or GNSS. The time change is handled centrally by the time server, without any human intervention:- The GPS/GNSS receiver knows the exact UTC time and the applicable DST rules per time zone
- The time server adjusts the local time automatically at the right moment
- All NTDS clocks on the network synchronise within seconds
Working internationally? Consider time zone clocks
If your organisation works internationally with offices, clients or partners in different time zones, the summer/winter time transition makes the time difference temporarily unpredictable. Teams meetings that normally take place at 15:00 Brussels time and 09:00 New York time suddenly shift by one hour due to the difference in changeover dates between Europe and the US.
A simple and permanent solution: time zone clocks at strategic locations in your company. Three clocks side by side, each set to a different time zone (for example Brussels, New York and Tokyo), give your team the current time difference at a glance, without calculations or doubt.
The Masterclock NTDS-8AL series is specially designed for time zone applications:
- Modular: up to 12 clocks side by side in a continuous row
- NTP-synchronised: each clock retrieves the time automatically via the network
- Automatic DST switching: configurable per clock which time zone rules apply
- City name label: below each display a programmable text (e.g. "BRUSSELS", "NEW YORK", "TOKYO")
Within the EU the transition is harmonised (Directive 2000/84/EC): on the last Sunday of March the clock goes forward at 01:00 UTC, on the last Sunday of October back at 01:00 UTC. For the Europe/Brussels zone that means locally 02:00 to 03:00 in spring and 03:00 to 02:00 in autumn, with a switch between CET (UTC+1) and CEST (UTC+2).
Technically it is crucial that systems work internally on UTC and apply summer time only at display via the time-zone database (IANA tz, for example Europe/Brussels). That way the underlying timeline stays continuous and unambiguous; only the local representation shifts. Clocks that hardcode local time produce errors at the transition, and the autumn hour of 02:00–03:00 exists locally twice, which makes logs ambiguous if there is no UTC reference.
An NTP- or GNSS-controlled clock keeps UTC and applies the configured time-zone rules automatically, so the transition happens without manual intervention and simultaneously across all clocks. Abolishing the biannual change has been discussed within the EU but has not entered into force.
Frequently asked questions? See the general FAQ on protocols, warranty, installation and support →
Need tailored advice?
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