Why a city clock changes after daylight saving time

A city clock can jump forward or back by an hour when daylight saving time begins or ends. If the change happens on a different date than you expected, or the time looks wrong afterward, the cause is usually the city’s time zone rules or a device setting.

Use the World Clock to check the local time in a city, then follow these checks to tell a normal seasonal change from an incorrect clock or time zone.

Check the city clock

1. Open the World Clock and look up the city whose time changed.
2. Check the city name and country. Many cities share names, and selecting the wrong one can show a different time zone.
3. Compare the displayed time with another city in the same region. Check whether the date changed too, since a time difference can cross midnight.
4. Look up the time difference using the city’s time zone, not a remembered UTC offset. The offset may have changed for daylight saving time.

A city clock may change its displayed time without anyone resetting it. A world clock applies the time zone’s rules to the date, including the dates when daylight saving time starts and ends.

What the change means

The clock moved forward by an hour

In a region that observes daylight saving time, clocks usually move forward by one hour when the switch begins. A local time such as 1:59 a.m. may be followed by 3:00 a.m., so times in that skipped hour do not occur on that date. If your city follows this rule and the date matches its switch, the change is expected.

The clock moved back by an hour

When daylight saving time ends, clocks usually move back by one hour. The hour between 1:00 and 2:00 a.m., for example, happens twice. This can make appointments or logs look duplicated if they show only the local time and not the time zone or offset.

The city changed on a different date

Daylight saving switches are not coordinated worldwide. Some places do not observe daylight saving time at all. Others change clocks on different dates, so two cities that usually have a familiar time difference may be an hour closer together or farther apart for a few weeks. Check the local rule for each city rather than assuming both switches happen together.

The displayed time is off by more than an hour

Check that you selected the intended city and that your device has the correct date and time. A wrong device clock can affect a web clock, while a manually chosen time zone can keep the device on the wrong local time even if its clock is accurate.

How to fix a city clock that looks wrong

1. Confirm the city. Search by both city and country, especially if the name is shared. Choose the city’s time zone rather than an entry that is only a fixed offset such as UTC-5.
2. Check your device’s date and time. On Windows 11, open Settings › Time & language › Date & time and turn on Set time automatically. On macOS, open System Settings › General › Date & Time and enable automatic date and time. On a phone, check Settings › General › Date & Time on iPhone, or Settings › System › Date & time on many Android phones. Menu names can vary by phone model.
3. Set the correct time zone. In Windows 11, check Settings › Time & language › Date & time and enable Set time zone automatically if available, or choose the correct zone manually. On macOS, use System Settings › General › Date & Time and enable automatic time zone setting, or select the correct region. On a phone, turn on automatic time zone in the date and time settings.
4. Reload the clock. Refresh the page or close and reopen the World Clock. This helps if the display was open while the time zone switched or the device resumed from sleep.
5. Update the device or browser if the rule is outdated. Time zone rules can change when governments change their daylight saving policy. Install pending system and browser updates, then check the city again.

Why the time difference changes

A time zone is more than a permanent number of hours ahead of or behind UTC, the international reference time. It also includes local rules about daylight saving time and the dates those rules apply. A city’s offset can therefore change during the year while its time zone name stays the same.

For example, a city that is normally five hours behind UTC may be four hours behind during daylight saving time. Another city may switch on a different date, temporarily changing the difference between them. For planned calls, use the cities’ local dates and times rather than calculating from a fixed offset. Why a world clock is safer than time zone math explains how this avoids common scheduling mistakes.

If the World Clock shows the expected local time but another device does not, check that device’s time zone and automatic date and time settings first.